Violet phosphorus,a recently explored layered elemental semiconductor,has attracted much attention due to its unique photoelectric,mechanical properties,and high hole mobility.Herein,violet arsenic phosphorus has for ...Violet phosphorus,a recently explored layered elemental semiconductor,has attracted much attention due to its unique photoelectric,mechanical properties,and high hole mobility.Herein,violet arsenic phosphorus has for the first time been synthesized by a molten lead method.The crystal structure of violet arsenic phosphorus(P^(83.4)As_(0.6),CSD-2408761)was determined by single crystal X-ray diffraction to have similar structure as that of violet phosphorus,where P12 is occupied by arsenic/phosphorus(As/P)atoms as mixed occupancy sites As1/P12.The arsenic substitution has been demonstrated to tune the band structure of violet phosphorus,switching p-type of violet phosphorus to high-performance n-type violet arsenic phosphorus.The effective electron mass along the<010>direction is significantly reduced from 1.792 to 0.515 m_(0)by arsenic substitution,resulting in an extremely high electron mobility of 2622.503 cm^(2)V^(-1)s^(-1).The field effect transistor built with P_(83.4)As_(0.6)nanosheets was measured to have a high electron mobility(137.06 cm^(2)V^(-1)s^(-1),61.2 nm),even under ambient conditions for 5 h,much higher than the hole mobility of violet phosphorene nanosheets(4.07 cm^(2)V^(-1)s^(-1),73.3 nm).This work provides a new idea for designing phosphorus-based materials for field effect transistors,giving significant potential in complementary metal-oxide-semiconductor applications.展开更多
Regioselevtive functionalization of perylene diimides(PDIs)at bay area often requires multistep synthesis and strenuous recrystallization.Direct bromination of perylene diimides only afford the 1,6 and 1,7-regioisomer...Regioselevtive functionalization of perylene diimides(PDIs)at bay area often requires multistep synthesis and strenuous recrystallization.Direct bromination of perylene diimides only afford the 1,6 and 1,7-regioisomers.More importantly,the 1,6-dibromo regioisomers could only be separated by preparative HPLC.Herein,we report a promising strategy for constructing Janus backbone of BN-doped perylene diimide derivatives.This Janus-type configuration results in the unique regioselective functionalization of BN-JPDIs,which yields exclusively the 1,6-regioisomers.Further investigation shows that the Janus-type configuration leads to a net dipole moment of 1.94 D and intramolecular charge transfer,which causes substantial changes on the optoelectronic properties.Moreover,the single crystal organic field-effect transistors based on BN-JPDIs exhibit electron mobilities up to 0.57 cm^(2)V^(-1)s^(-1),showcasing their potential as versatile building block towards high-performance n-type organic semiconductors.展开更多
Titanium-based semiconductors are known for their high chemical stability and suitable band gap widths.However,the conventional experimental screening methods are inefficient due to the wide variety of materials.To sp...Titanium-based semiconductors are known for their high chemical stability and suitable band gap widths.However,the conventional experimental screening methods are inefficient due to the wide variety of materials.To speed up the selection process,this work focuses on interpretable feature learning and band gap prediction for titanium-based semiconductors.First,titanium compounds were selected from the Materials Project database by machine learning,and elemental features were extracted using the Magpie descriptors.Then,principal component analysis(PCA)was applied to reduce the data dimensionality,creating a representative dataset.Meantime,heatmaps and SHAP(SHapley Additive exPlanations)methods were used to demonstrate the influence of key features such as electronegativity,covalent radius,period number,and unit cell volume on the bandgap,understanding the relationship between the material’s properties and performance.After comparing different machine learning models,including Random Forest(RF),Support Vector Machines(SVM),Linear Regression(LR),and Gradient Boosting Regression(GBR),the RF was found to be the most accurate for band gap prediction.Finally,the model performance was improved through parameter tuning,showing high accuracy.These findings provide strong data support and design guidance for the development of materials in fields like photocatalysis and solar cells.展开更多
Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully construct...Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24.展开更多
Thermocells are attracting growing interest as a promising thermoelectric technology for low-grade heat harvesting.However,the scarcity of high-performance redox couples featuring intrinsically high thermopower(Se)and...Thermocells are attracting growing interest as a promising thermoelectric technology for low-grade heat harvesting.However,the scarcity of high-performance redox couples featuring intrinsically high thermopower(Se)and fast redox kinetics hinders the rapid development of thermocells.Identifying potential intrinsically high-performance redox couples remains a significant challenge.This work introduces a novel n-type copper(I/II)chloride(CuCl/CuCl2)redox couple with intrinsically high performance.Through tailored electrolyte design,long-term stability was significantly improved by reducing proton concentration to suppress cuprous ion photo-oxidation,while ammonium chloride solvation enhanced cuprous ion solubility.The resulting system achieves a Se value closely aligned with theoretical predictions and exhibits rapid redox kinetics.Consequently,the optimized CuCl/CuCl_(2) intrinsic system demonstrated a high S_(e) of 1.52 mV K^(−1) and a record-high normalized power density Pmax(ΔT)^(−2) of 0.399 mW m^(−2) K^(−2),surpassing previously reported intrinsic n-type thermocells and rivaling the performance of p-type pristine 0.4 M ferri/ferrocyanide systems.A prototype module comprising 30 p-n units successfully powered a line of light-emitting diodes or a thermohygrometer.This work introduces a valuable redox couple for further advancing high-performance thermocells and demonstrates a viable strategy for developing novel redox systems.展开更多
Efficient photo-patterning of polymer semiconductors with cross-linkers has emerged as a promising route to fabricate organic integrated circuits via all-solution processing techniques.Herein,we report a new four-arme...Efficient photo-patterning of polymer semiconductors with cross-linkers has emerged as a promising route to fabricate organic integrated circuits via all-solution processing techniques.Herein,we report a new four-armed diazo-based oligomer photo-crosslinker 2DPP4N_(2)for the patterning of semiconducting polymers by UV light-induced crossing-linking reaction.After blending 2DPP4N_(2)with polymer semiconductors such as PDPP4T(p-type),PDPP3T(ambipolar)and N2200(n-type),we prepared various patterns with a resolution of 6μm by irradiating through a photo-mask with 254 nm UV light for 160 s.Notably,the interchain packing and surface morphology remained nearly unchanged after photo-patterning,as characterized by atomic force microscopy(AFM)and grazing incidence wide-angle X-ray scattering(GIWAXS).Consequently,the charge transport property of the patterned thin film was largely maintained in comparison to that of its pristine thin film.These results reveal that 2DPP4N_(2)is a viable and promising candidate for application in all-solution-processable flexible integrated electronic devices.展开更多
Piezoelectric semiconductor(PSC)materials exhibit strong electromechanical coupling affected by free carriers,which makes their contact behavior essential for sensors,actuators,and electronic devices.Analytical models...Piezoelectric semiconductor(PSC)materials exhibit strong electromechanical coupling affected by free carriers,which makes their contact behavior essential for sensors,actuators,and electronic devices.Analytical models for three-dimensional(3D)PSC contact problems are still scarce,especially for conductive indenters.This work develops a semi-analytical framework to study the 3D frictionless contact between a conductive indenter and a PSC half-space.Fundamental solutions under a unit force and a unit electric charge are derived,and the corresponding frequency response functions are combined with a discrete convolution-fast Fourier transform(DC-FFT)algorithm to achieve an efficient semi-analytical contact model.The numerical results demonstrate that an increase in the surface charge density reduces the indentation pressure and modifies the electric potential distribution.A higher steady carrier concentration enhances the screening effect,suppresses the electromechanical coupling,and shifts the system response toward purely elastic behaviors.The sensitivity analysis shows that the indentation depth is dominated by the elastic constants,while the electric potential is mainly affected by the piezoelectric coefficient.Although the analysis is carried out with spherical indenters,the model is not limited to a specific indenter shape.It provides an effective tool for investigating complex 3D PSC contact problems and offers useful insights into the design of PSC materials-based devices.展开更多
Oxide semiconductors(OSs),introduced by the Hosono group in the early 2000s,have evolved from display backplane materials to promising candidates for advanced memory and logic devices.The exceptionally low leakage cur...Oxide semiconductors(OSs),introduced by the Hosono group in the early 2000s,have evolved from display backplane materials to promising candidates for advanced memory and logic devices.The exceptionally low leakage current of OSs and compatibility with three-dimensional(3D)architectures have recently sparked renewed interest in their use in semiconductor applications.This review begins by exploring the unique material properties of OSs,which fundamentally originate from their distinct electronic band structure.Subsequently,we focus on atomic layer deposition(ALD),a core technique for growing excellent OS films,covering both basic and advanced processes compatible with 3D scaling.The basic surface reaction mechanisms—adsorption and reaction—and their roles in film growth are introduced.Furthermore,material design strategies,such as cation selection,crystallinity control,anion doping,and heterostructure engineering,are discussed.We also highlight challenges in memory applications,including contact resistance,hydrogen instability,and lack of p-type materials,and discuss the feasibility of ALD-grown OSs as potential solutions.Lastly,we provide an outlook on the role of ALD-grown OSs in memory technologies.This review bridges material fundamentals and device-level requirements,offering a comprehensive perspective on the potential of ALD-driven OSs for next-generation semiconductor memory devices.展开更多
Due to the intrinsic interaction between piezoelectric effects and semiconducting properties,piezoelectric semiconductors(PSs)have great promise for applications in multi-functional electronic devices,requiring a deep...Due to the intrinsic interaction between piezoelectric effects and semiconducting properties,piezoelectric semiconductors(PSs)have great promise for applications in multi-functional electronic devices,requiring a deep understanding of the multi-field coupling behavior.This work investigates the free vibration and buckling characteristics of a PS beam under different mechanical boundary conditions.The coupling fields of a PS beam are modeled by combining the Timoshenko beam theory for mechanical fields with a high-order expansion along the beam thickness for electric fields and carrier distributions.Based on the hypothesis of small perturbation of carrier density,the governing equations and boundary conditions are derived with the principle of virtual work.The differential quadrature method(DQM)is used to solve the boundary-value problem.The analytical solutions for a simply supported-simply supported(SS)PS beam are also obtained for verification.The convergence and correctness of the solutions obtained with the DQM are first evaluated.Subsequently,the effects of initial electron density,boundary conditions,and geometric parameters on the vibration and buckling characteristics are explored through numerical examples,where the finite element simulations are also included.The interaction mechanism of multi-physics fields is revealed.The scale effect on the static and dynamic responses of a PS beam is demonstrated.The derived model and findings are useful for the analysis and design of PS-based devices.展开更多
Understanding the fracture behavior of vertical cracks in piezoelectric semiconductor(PS)structures is vital due to their impacts on device reliability.This study establishes a model for a PS strip with a vertical cra...Understanding the fracture behavior of vertical cracks in piezoelectric semiconductor(PS)structures is vital due to their impacts on device reliability.This study establishes a model for a PS strip with a vertical crack under combined mechanical and electric loading,considering both central and edge cracks.Using Fourier transforms and dislocation density functions,the Mode-Ⅲproblem is converted to Cauchy-type singular integral equations.The crack surface fields,intensity factors,and energy release rate are derived.The accuracy of the proposed model is verified through the finite element(FE)simulation via COMSOL Multiphysics.The results for low electron concentrations align with those of the intrinsic piezoelectric materials,validating the correctness of the present model as well.The combined effects of crack position,applied electric loading,and initial carrier concentration on the crack propagation are analyzed.The normalized electric displacement factor shows heightened sensitivity to crack size,electromechanical loading,and carrier concentration.The crack position significantly influences the crack surface fields and normalized intensity factors due to the boundary proximity effect.展开更多
The influence of total dose irradiation on hot-carrier reliability of 65 nm n-type metal-oxide-semiconductor field- effect transistors （nMOSFETs） is investigated. Experimental results show that hot-carrier degradati...The influence of total dose irradiation on hot-carrier reliability of 65 nm n-type metal-oxide-semiconductor field- effect transistors （nMOSFETs） is investigated. Experimental results show that hot-carrier degradations on ir- radiated narrow channel nMOSFETs are greater than those without irradiation. The reason is attributed to radiation-induced charge trapping in shallow trench isolation （STI）. The electric field in the pinch-off region of the nMOSFET is enhanced by radiation-induced charge trapping in STI, resulting in a more severe hot-carrier effect.展开更多
Polymer semiconductors have aroused interests from both academic and industry due to their wide applications in electronic devices,such as organic thin-film transistors(OT-FTs)[1],polymer solar cells(PSCs)[2−6],organi...Polymer semiconductors have aroused interests from both academic and industry due to their wide applications in electronic devices,such as organic thin-film transistors(OT-FTs)[1],polymer solar cells(PSCs)[2−6],organic thermoelectrics(OTEs)[7−11],and perovskite solar cells(PVSCs)[12−14].To date,great efforts have been devoted to developing p-type poly-mer semiconductors,while the development of n-type poly-mers lags far behind.In fact,n-type polymers are essential for organic electronic devices.展开更多
Herein,we propose a new strategy to develop air-stable n-type organic semiconductors with non-classical thiophene aromatic diimide derivatives by replacing aromatic naphthalene with a heteroaromatic isothianaphthene c...Herein,we propose a new strategy to develop air-stable n-type organic semiconductors with non-classical thiophene aromatic diimide derivatives by replacing aromatic naphthalene with a heteroaromatic isothianaphthene core.We designed and successfully synthesized the isothianaphthene core based diimide material,N,N′-bis(n-hexyl)isothianaphthene-2,3,6,7-tetracarboxylic acid diimide(BTDI-C6)as an n-type semiconductor.Compared to N,N′-bis(n-hexyl)naphthalene-1,4,5,8-tetracarboxylic acid diimide(NDI-C6),BTDI-C6 possesses a deeper LUMO energy level of-4.21 eV,which is 0.32 eV lower than that of NDI-C6.Both molecular modelling and experimental results elucidated that organic thin film transistors(OTFTs)based on both of these materials exhibit comparable mobilities;however,the threshold voltage of BTDI-C6 based device(+7.5 V)is significantly lower than that of NDI-C6 based counterpart(+34V).Moreover,the low-lying LUMO energy level of BTDI-C6 ensures excellent air-stability which is further validated by the device performance.In addition,BTDI-C6 shows high luminescence while NDI-C6 is not luminescent at all in solution,which reveals the potential application of our newly synthesized material in n-type light-emitting transistors.展开更多
The n-type ultrathin fully depleted silicon-on-insulator(FDSOI) metal-oxide-semiconductor field-effect transistors(MOSFETs),with a Hf_(0.5)Zr_(0.5)O_(2) high dielectric permittivity(high-k) dielectric as gate insulato...The n-type ultrathin fully depleted silicon-on-insulator(FDSOI) metal-oxide-semiconductor field-effect transistors(MOSFETs),with a Hf_(0.5)Zr_(0.5)O_(2) high dielectric permittivity(high-k) dielectric as gate insulator,were fabricated.The total ionizing dose effects were investigated,and an X-ray radiation dose up to 1500 krad(Si) was applied for both long-and short-channel devices.The short-channel devices(0.025-0.100 μm) exhibited less irradiation sensitivity compared with the long-channel devices(0.35-16 μm),leading to a 71% reduction in the irradiation-induced drain current growth and a 26% decrease in the shift of the threshold voltage.It was experimentally demonstrated that the OFF mode is the worst case among the three working conditions(OFF,ON and A110) for short-channel devices.Also,the determined effective electron mobility was enhanced by 38% after X-ray irradiation,attributed to the different compensations for charges triggered by radiation between the highk dielectric and buried oxide.By extracting the carrier mobility,gate length modulation,and source/drain(S/D)parasitic resistance,the degradation mechanism on X-ray irradiation was revealed.Finally,the split capacitance-voltage measurements were used to validate the analysis.展开更多
Semiconductor optoelectronics devices,capable of converting electrical power into light or conversely light into electrical power in a compact and highly efficient manner represent one of the most advanced technologie...Semiconductor optoelectronics devices,capable of converting electrical power into light or conversely light into electrical power in a compact and highly efficient manner represent one of the most advanced technologies ever developed,which has profoundly reshaped the modern life with a wide range of applications.In recent decades,semiconductor technology has rapidly evolved from first-generation narrow bandgap materials(Si,Ge)to the latest fourth-generation ultra-wide bandgap semiconductor(GaO,diamond,AlN)with enhanced performance to meet growing demands.Additionally,merging semiconductor devices with other techniques,such as computer assisted design,state-of-the-art micro/nano fabrications,novel epitaxial growth,have significantly accelerated the development of semiconductor optoelectronics devices.Among them,integrating metasurfaces with semiconductor optoelectronic devices have opened new frontiers for on-chip control of their electromagnetic response,providing access to previously inaccessible degrees of freedom.We review the recent advances in on-chip control of a variety of semiconductor optoelectronic devices using integrated metasurfaces,including semiconductor lasers,semiconductor light emitting devices,semiconductor photodetectors,and low dimensional semiconductors.The integration of metasurfaces with semiconductors offers wafer-level ultracompact solutions for manipulating the functionalities of semiconductor devices,while also providing a practical platform for implementing cuttingedge metasurface technology in real-world applications.展开更多
In this paper,we theoretically study the Lamb wave in a multilayered piezoelectric semiconductor(PSC)plate,where each layer is an n-type PSC with the symmetry of transverse isotropy.Based on the extended Stroh formali...In this paper,we theoretically study the Lamb wave in a multilayered piezoelectric semiconductor(PSC)plate,where each layer is an n-type PSC with the symmetry of transverse isotropy.Based on the extended Stroh formalism and dual-variable and position(DVP)method,the general solution of the coupled fields for the Lamb wave is derived,and then the dispersion equation is obtained by the application of the boundary conditions.First,the influence of semiconducting properties on the dispersion behavior of the Lamb wave in a single-layer PSC plate is analyzed.Then,the propagation characteristics of the Lamb wave in a sandwich plate are investigated in detail.The numerical results show that the wave speed and attenuation depend on the stacking sequence,layer thickness,and initial carrier density,the Lamb wave can propagate without a cut-off frequency in both the homogeneous and multilayer PSC plates due to the semiconducting properties,and the Lamb wave without attenuation can be achieved by carefully selecting the semiconductor property in the upper and lower layers.These new features could be very helpful as theoretical guidance for the design and performance optimization of PSC devices.展开更多
Workpiece rotational grinding is widely used in the ultra-precision machining of hard and brittle semiconductor materials,including single-crystal silicon,silicon carbide,and gallium arsenide.Surface roughness and sub...Workpiece rotational grinding is widely used in the ultra-precision machining of hard and brittle semiconductor materials,including single-crystal silicon,silicon carbide,and gallium arsenide.Surface roughness and subsurface damage depth(SDD)are crucial indicators for evaluating the surface quality of these materials after grinding.Existing prediction models lack general applicability and do not accurately account for the complex material behavior under grinding conditions.This paper introduces novel models for predicting both surface roughness and SDD in hard and brittle semiconductor materials.The surface roughness model uniquely incorporates the material’s elastic recovery properties,revealing the significant impact of these properties on prediction accuracy.The SDD model is distinguished by its analysis of the interactions between abrasive grits and the workpiece,as well as the mechanisms governing stress-induced damage evolution.The surface roughness model and SDD model both establish a stable relationship with the grit depth of cut(GDC).Additionally,we have developed an analytical relationship between the GDC and grinding process parameters.This,in turn,enables the establishment of an analytical framework for predicting surface roughness and SDD based on grinding process parameters,which cannot be achieved by previous models.The models were validated through systematic experiments on three different semiconductor materials,demonstrating excellent agreement with experimental data,with prediction errors of 6.3%for surface roughness and6.9%for SDD.Additionally,this study identifies variations in elastic recovery and material plasticity as critical factors influencing surface roughness and SDD across different materials.These findings significantly advance the accuracy of predictive models and broaden their applicability for grinding hard and brittle semiconductor materials.展开更多
We present a theoretical scheme to realize two-dimensional(2D)asymmetric diffraction grating in a five-level inverted Y-type asymmetric double semiconductor quantum wells(SQWs)structure with resonant tunneling.The SQW...We present a theoretical scheme to realize two-dimensional(2D)asymmetric diffraction grating in a five-level inverted Y-type asymmetric double semiconductor quantum wells(SQWs)structure with resonant tunneling.The SQW structure interacts with a weak probe laser field,a spatially independent 2D standing-wave(SW)field,and a Laguerre–Gaussian(LG)vortex field,respectively.The results indicate that the diffraction patterns are highly sensitive to amplitude modulation and phase modulation.Because of the existence of vortex light,it is possible to realize asymmetric high-order diffraction in the SQW structure,and then a 2D asymmetric grating is established.By adjusting the detunings of the probe field,vortex field,and SW field,as well as the interaction length,diffraction intensity,and direction of the 2D asymmetric electromagnetically induced grating(EIG)can be controlled effectively.In addition,the number of orbital angular momenta(OAM)and beam waist parameter can be used to modulate the diffraction intensity and energy transfer of the probe light in different regions.High-order diffraction intensity is enhanced and high-efficiency 2D asymmetric diffraction grating with different diffraction patterns is obtained in the scheme.Such 2D asymmetric diffraction grating may be beneficial to the research of optical communication and innovative semiconductor quantum devices.展开更多
Although there are numerous optical spectroscopy techniques and methods that have been used to extract the fundamental bandgap of a semiconductor,most of them belong to one of these three approaches:(1)the excitonic a...Although there are numerous optical spectroscopy techniques and methods that have been used to extract the fundamental bandgap of a semiconductor,most of them belong to one of these three approaches:(1)the excitonic absorption,(2)modulation spectroscopy,and(3)the most widely used Tauc-plot.The excitonic absorption is based on a many-particle theory,which is physically the most correct approach,but requires more stringent crystalline quality and appropriate sample preparation and experimental implementation.The Tauc-plot is based on a single-particle theo⁃ry that neglects the many-electron effects.Modulation spectroscopy analyzes the spectroscopy features in the derivative spectrum,typically,of the reflectance and transmission under an external perturbation.Empirically,the bandgap ener⁃gy derived from the three approaches follow the order of E_(ex)>E_(MS)>E_(TP),where three transition energies are from exci⁃tonic absorption,modulation spectroscopy,and Tauc-plot,respectively.In principle,defining E_(g) as the single-elec⁃tron bandgap,we expect E_(g)>E_(ex),thus,E_(g)>E_(TP).In the literature,E_(TP) is often interpreted as E_(g),which is conceptual⁃ly problematic.However,in many cases,because the excitonic peaks are not readily identifiable,the inconsistency be⁃tween E_(g) and E_(TP) becomes invisible.In this brief review,real world examples are used(1)to illustrate how excitonic absorption features depend sensitively on the sample and measurement conditions;(2)to demonstrate the differences between E_(ex),E_(MS),and E_(TP) when they can be extracted simultaneously for one sample;and(3)to show how the popular⁃ly adopted Tauc-plot could lead to misleading results.Finally,it is pointed out that if the excitonic absorption is not ob⁃servable,the modulation spectroscopy can often yield a more useful and reasonable bandgap than Tauc-plot.展开更多
Radiation doses to patients in diagnostics and interventional radiology need to be optimized to comply with the principles of radiation protection in medical practice. This involves using specific detectors with respe...Radiation doses to patients in diagnostics and interventional radiology need to be optimized to comply with the principles of radiation protection in medical practice. This involves using specific detectors with respective diagnostic beams to carry out quality control/quality assurance tests needed to optimize patient doses in the hospital. Semiconductor detectors are used in dosimetry to verify the equipment performance and dose to patients. This work aims to assess the performance, energy dependence, and response of five commercially available semiconductor detectors in RQR, RQR-M, RQA, and RQT at Secondary Standard Dosimetry for clinical applications. The diagnostic beams were generated using Exradin A4 reference ion chamber and PTW electrometer. The ambient temperature and pressure were noted for KTP correction. The detectors designed for RQR showed good performance in RQT beams and vice versa. The detectors designed for RQR-M displayed high energy dependency in other diagnostic beams. The type of diagnostic beam quality determines the response of semiconductor detectors. Therefore, a detector should be calibrated according to the beam qualities to be measured.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.22175136)the State Key Laboratory of Electrical Insulation and Power Equipment(Grant No.EIPE23127)the Fundamental Research Funds for the Central Universities(xtr052024009,xtr052025002).
文摘Violet phosphorus,a recently explored layered elemental semiconductor,has attracted much attention due to its unique photoelectric,mechanical properties,and high hole mobility.Herein,violet arsenic phosphorus has for the first time been synthesized by a molten lead method.The crystal structure of violet arsenic phosphorus(P^(83.4)As_(0.6),CSD-2408761)was determined by single crystal X-ray diffraction to have similar structure as that of violet phosphorus,where P12 is occupied by arsenic/phosphorus(As/P)atoms as mixed occupancy sites As1/P12.The arsenic substitution has been demonstrated to tune the band structure of violet phosphorus,switching p-type of violet phosphorus to high-performance n-type violet arsenic phosphorus.The effective electron mass along the<010>direction is significantly reduced from 1.792 to 0.515 m_(0)by arsenic substitution,resulting in an extremely high electron mobility of 2622.503 cm^(2)V^(-1)s^(-1).The field effect transistor built with P_(83.4)As_(0.6)nanosheets was measured to have a high electron mobility(137.06 cm^(2)V^(-1)s^(-1),61.2 nm),even under ambient conditions for 5 h,much higher than the hole mobility of violet phosphorene nanosheets(4.07 cm^(2)V^(-1)s^(-1),73.3 nm).This work provides a new idea for designing phosphorus-based materials for field effect transistors,giving significant potential in complementary metal-oxide-semiconductor applications.
基金support from the National Natural Science Foundation of China(Nos.22071007,22020102001,22335002)the National Key R&D Program of China(No.2022YFB3602802)+3 种基金Beijing Natural Science Foundation(No.Z220025)the National Facility for Protein Science in Shanghai,Shanghai Advanced Research Institute,CAS,for providing technical support in X-ray diffraction data collectionthe High-Performance Computing Platform of Peking University for supporting the computational workthe support of BMS Junior Fellow program。
文摘Regioselevtive functionalization of perylene diimides(PDIs)at bay area often requires multistep synthesis and strenuous recrystallization.Direct bromination of perylene diimides only afford the 1,6 and 1,7-regioisomers.More importantly,the 1,6-dibromo regioisomers could only be separated by preparative HPLC.Herein,we report a promising strategy for constructing Janus backbone of BN-doped perylene diimide derivatives.This Janus-type configuration results in the unique regioselective functionalization of BN-JPDIs,which yields exclusively the 1,6-regioisomers.Further investigation shows that the Janus-type configuration leads to a net dipole moment of 1.94 D and intramolecular charge transfer,which causes substantial changes on the optoelectronic properties.Moreover,the single crystal organic field-effect transistors based on BN-JPDIs exhibit electron mobilities up to 0.57 cm^(2)V^(-1)s^(-1),showcasing their potential as versatile building block towards high-performance n-type organic semiconductors.
文摘Titanium-based semiconductors are known for their high chemical stability and suitable band gap widths.However,the conventional experimental screening methods are inefficient due to the wide variety of materials.To speed up the selection process,this work focuses on interpretable feature learning and band gap prediction for titanium-based semiconductors.First,titanium compounds were selected from the Materials Project database by machine learning,and elemental features were extracted using the Magpie descriptors.Then,principal component analysis(PCA)was applied to reduce the data dimensionality,creating a representative dataset.Meantime,heatmaps and SHAP(SHapley Additive exPlanations)methods were used to demonstrate the influence of key features such as electronegativity,covalent radius,period number,and unit cell volume on the bandgap,understanding the relationship between the material’s properties and performance.After comparing different machine learning models,including Random Forest(RF),Support Vector Machines(SVM),Linear Regression(LR),and Gradient Boosting Regression(GBR),the RF was found to be the most accurate for band gap prediction.Finally,the model performance was improved through parameter tuning,showing high accuracy.These findings provide strong data support and design guidance for the development of materials in fields like photocatalysis and solar cells.
文摘Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24.
基金supported by research grants from Innovative Research Group Project of National Natural Science Foundation of China(52021004)the National Key Research and Development Program of China(2022YFB3803300)+1 种基金the National Natural Science Foundation of China(62474026,62205140,and 12204071)the China Postdoctoral Science Foundation(2022M710532).
文摘Thermocells are attracting growing interest as a promising thermoelectric technology for low-grade heat harvesting.However,the scarcity of high-performance redox couples featuring intrinsically high thermopower(Se)and fast redox kinetics hinders the rapid development of thermocells.Identifying potential intrinsically high-performance redox couples remains a significant challenge.This work introduces a novel n-type copper(I/II)chloride(CuCl/CuCl2)redox couple with intrinsically high performance.Through tailored electrolyte design,long-term stability was significantly improved by reducing proton concentration to suppress cuprous ion photo-oxidation,while ammonium chloride solvation enhanced cuprous ion solubility.The resulting system achieves a Se value closely aligned with theoretical predictions and exhibits rapid redox kinetics.Consequently,the optimized CuCl/CuCl_(2) intrinsic system demonstrated a high S_(e) of 1.52 mV K^(−1) and a record-high normalized power density Pmax(ΔT)^(−2) of 0.399 mW m^(−2) K^(−2),surpassing previously reported intrinsic n-type thermocells and rivaling the performance of p-type pristine 0.4 M ferri/ferrocyanide systems.A prototype module comprising 30 p-n units successfully powered a line of light-emitting diodes or a thermohygrometer.This work introduces a valuable redox couple for further advancing high-performance thermocells and demonstrates a viable strategy for developing novel redox systems.
基金supported by the National Natural Science Foundation of China(No.22205242)。
文摘Efficient photo-patterning of polymer semiconductors with cross-linkers has emerged as a promising route to fabricate organic integrated circuits via all-solution processing techniques.Herein,we report a new four-armed diazo-based oligomer photo-crosslinker 2DPP4N_(2)for the patterning of semiconducting polymers by UV light-induced crossing-linking reaction.After blending 2DPP4N_(2)with polymer semiconductors such as PDPP4T(p-type),PDPP3T(ambipolar)and N2200(n-type),we prepared various patterns with a resolution of 6μm by irradiating through a photo-mask with 254 nm UV light for 160 s.Notably,the interchain packing and surface morphology remained nearly unchanged after photo-patterning,as characterized by atomic force microscopy(AFM)and grazing incidence wide-angle X-ray scattering(GIWAXS).Consequently,the charge transport property of the patterned thin film was largely maintained in comparison to that of its pristine thin film.These results reveal that 2DPP4N_(2)is a viable and promising candidate for application in all-solution-processable flexible integrated electronic devices.
基金Project supported by the National Natural Science Foundation of China(No.12402113)the Sichuan Science and Technology Program(No.2024NSFSC0037)。
文摘Piezoelectric semiconductor(PSC)materials exhibit strong electromechanical coupling affected by free carriers,which makes their contact behavior essential for sensors,actuators,and electronic devices.Analytical models for three-dimensional(3D)PSC contact problems are still scarce,especially for conductive indenters.This work develops a semi-analytical framework to study the 3D frictionless contact between a conductive indenter and a PSC half-space.Fundamental solutions under a unit force and a unit electric charge are derived,and the corresponding frequency response functions are combined with a discrete convolution-fast Fourier transform(DC-FFT)algorithm to achieve an efficient semi-analytical contact model.The numerical results demonstrate that an increase in the surface charge density reduces the indentation pressure and modifies the electric potential distribution.A higher steady carrier concentration enhances the screening effect,suppresses the electromechanical coupling,and shifts the system response toward purely elastic behaviors.The sensitivity analysis shows that the indentation depth is dominated by the elastic constants,while the electric potential is mainly affected by the piezoelectric coefficient.Although the analysis is carried out with spherical indenters,the model is not limited to a specific indenter shape.It provides an effective tool for investigating complex 3D PSC contact problems and offers useful insights into the design of PSC materials-based devices.
基金supported by National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(MSIT)(No.RS-2023-00260527,RS-2024-00407282,RS-2025-00557667)supported by Hanyang University Industry-University Cooperation Foundation(No.202400000003943)supported by Korea Planning&Evaluation Institute of Industrial Technology(KEIT)funded by South Korean Ministry of Trade,Industry and Energy(MOTIE)(No.RS-2025-25454815,RS-2025-02308064,20017382)。
文摘Oxide semiconductors(OSs),introduced by the Hosono group in the early 2000s,have evolved from display backplane materials to promising candidates for advanced memory and logic devices.The exceptionally low leakage current of OSs and compatibility with three-dimensional(3D)architectures have recently sparked renewed interest in their use in semiconductor applications.This review begins by exploring the unique material properties of OSs,which fundamentally originate from their distinct electronic band structure.Subsequently,we focus on atomic layer deposition(ALD),a core technique for growing excellent OS films,covering both basic and advanced processes compatible with 3D scaling.The basic surface reaction mechanisms—adsorption and reaction—and their roles in film growth are introduced.Furthermore,material design strategies,such as cation selection,crystallinity control,anion doping,and heterostructure engineering,are discussed.We also highlight challenges in memory applications,including contact resistance,hydrogen instability,and lack of p-type materials,and discuss the feasibility of ALD-grown OSs as potential solutions.Lastly,we provide an outlook on the role of ALD-grown OSs in memory technologies.This review bridges material fundamentals and device-level requirements,offering a comprehensive perspective on the potential of ALD-driven OSs for next-generation semiconductor memory devices.
基金Project supported by the National Natural Science Foundation of China(Nos.U21A20430 and 12472155)the Natural Science Foundation of Hebei Province of China(No.A2024210002)。
文摘Due to the intrinsic interaction between piezoelectric effects and semiconducting properties,piezoelectric semiconductors(PSs)have great promise for applications in multi-functional electronic devices,requiring a deep understanding of the multi-field coupling behavior.This work investigates the free vibration and buckling characteristics of a PS beam under different mechanical boundary conditions.The coupling fields of a PS beam are modeled by combining the Timoshenko beam theory for mechanical fields with a high-order expansion along the beam thickness for electric fields and carrier distributions.Based on the hypothesis of small perturbation of carrier density,the governing equations and boundary conditions are derived with the principle of virtual work.The differential quadrature method(DQM)is used to solve the boundary-value problem.The analytical solutions for a simply supported-simply supported(SS)PS beam are also obtained for verification.The convergence and correctness of the solutions obtained with the DQM are first evaluated.Subsequently,the effects of initial electron density,boundary conditions,and geometric parameters on the vibration and buckling characteristics are explored through numerical examples,where the finite element simulations are also included.The interaction mechanism of multi-physics fields is revealed.The scale effect on the static and dynamic responses of a PS beam is demonstrated.The derived model and findings are useful for the analysis and design of PS-based devices.
基金Project supported by the Guangdong Basic and Applied Basic Research Foundation of China(Nos.2022B1515020099 and 2024A1515240026)the National Natural Science Foundation of China(No.12372147)the Fundamental Research Funds for the Central Universities of China(No.HIT.OCEF.2024019)。
文摘Understanding the fracture behavior of vertical cracks in piezoelectric semiconductor(PS)structures is vital due to their impacts on device reliability.This study establishes a model for a PS strip with a vertical crack under combined mechanical and electric loading,considering both central and edge cracks.Using Fourier transforms and dislocation density functions,the Mode-Ⅲproblem is converted to Cauchy-type singular integral equations.The crack surface fields,intensity factors,and energy release rate are derived.The accuracy of the proposed model is verified through the finite element(FE)simulation via COMSOL Multiphysics.The results for low electron concentrations align with those of the intrinsic piezoelectric materials,validating the correctness of the present model as well.The combined effects of crack position,applied electric loading,and initial carrier concentration on the crack propagation are analyzed.The normalized electric displacement factor shows heightened sensitivity to crack size,electromechanical loading,and carrier concentration.The crack position significantly influences the crack surface fields and normalized intensity factors due to the boundary proximity effect.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11475255,U1532261 and 11505282
文摘The influence of total dose irradiation on hot-carrier reliability of 65 nm n-type metal-oxide-semiconductor field- effect transistors （nMOSFETs） is investigated. Experimental results show that hot-carrier degradations on ir- radiated narrow channel nMOSFETs are greater than those without irradiation. The reason is attributed to radiation-induced charge trapping in shallow trench isolation （STI）. The electric field in the pinch-off region of the nMOSFET is enhanced by radiation-induced charge trapping in STI, resulting in a more severe hot-carrier effect.
基金the Doctoral Research Initiation Foundation of Anhui Normal University(752091)L.Ding appreciates the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21772030,51922032,21961160720)for financial support.
文摘Polymer semiconductors have aroused interests from both academic and industry due to their wide applications in electronic devices,such as organic thin-film transistors(OT-FTs)[1],polymer solar cells(PSCs)[2−6],organic thermoelectrics(OTEs)[7−11],and perovskite solar cells(PVSCs)[12−14].To date,great efforts have been devoted to developing p-type poly-mer semiconductors,while the development of n-type poly-mers lags far behind.In fact,n-type polymers are essential for organic electronic devices.
基金supported by Shenzhen Science and Technology (JCYJ20170412151139619)Shenzhen Engineering Laboratory (Shenzhen development and reform commission [2016]1592)+1 种基金Guangdong Key Research Project (2019B010924003), Guangdong International Science Collaboration Base (2019A050505003)Shenzhen Peacock Plan (KQTD2014062714543296)
文摘Herein,we propose a new strategy to develop air-stable n-type organic semiconductors with non-classical thiophene aromatic diimide derivatives by replacing aromatic naphthalene with a heteroaromatic isothianaphthene core.We designed and successfully synthesized the isothianaphthene core based diimide material,N,N′-bis(n-hexyl)isothianaphthene-2,3,6,7-tetracarboxylic acid diimide(BTDI-C6)as an n-type semiconductor.Compared to N,N′-bis(n-hexyl)naphthalene-1,4,5,8-tetracarboxylic acid diimide(NDI-C6),BTDI-C6 possesses a deeper LUMO energy level of-4.21 eV,which is 0.32 eV lower than that of NDI-C6.Both molecular modelling and experimental results elucidated that organic thin film transistors(OTFTs)based on both of these materials exhibit comparable mobilities;however,the threshold voltage of BTDI-C6 based device(+7.5 V)is significantly lower than that of NDI-C6 based counterpart(+34V).Moreover,the low-lying LUMO energy level of BTDI-C6 ensures excellent air-stability which is further validated by the device performance.In addition,BTDI-C6 shows high luminescence while NDI-C6 is not luminescent at all in solution,which reveals the potential application of our newly synthesized material in n-type light-emitting transistors.
基金financially supported by the National Natural Science Foundation of China (Nos.61874135,61904194 and 11905287)the National Major Project of Science and Technology of China (No.2017ZX02315001)+1 种基金the Youth Innovation Promotion Association,CAS (No.Y9YQ01R004)the Opening Project of Key Laboratory of Microelectronic Devices & Integrated Technology,Institute of Microelectronics,CAS (No.Y9YS05X002)。
文摘The n-type ultrathin fully depleted silicon-on-insulator(FDSOI) metal-oxide-semiconductor field-effect transistors(MOSFETs),with a Hf_(0.5)Zr_(0.5)O_(2) high dielectric permittivity(high-k) dielectric as gate insulator,were fabricated.The total ionizing dose effects were investigated,and an X-ray radiation dose up to 1500 krad(Si) was applied for both long-and short-channel devices.The short-channel devices(0.025-0.100 μm) exhibited less irradiation sensitivity compared with the long-channel devices(0.35-16 μm),leading to a 71% reduction in the irradiation-induced drain current growth and a 26% decrease in the shift of the threshold voltage.It was experimentally demonstrated that the OFF mode is the worst case among the three working conditions(OFF,ON and A110) for short-channel devices.Also,the determined effective electron mobility was enhanced by 38% after X-ray irradiation,attributed to the different compensations for charges triggered by radiation between the highk dielectric and buried oxide.By extracting the carrier mobility,gate length modulation,and source/drain(S/D)parasitic resistance,the degradation mechanism on X-ray irradiation was revealed.Finally,the split capacitance-voltage measurements were used to validate the analysis.
基金supported by the National Natural Science Foundation of China(62374150)Natural Science Foundation of Henan(242300421216)+3 种基金C.Zheng acknowledges the support of China Postdoctoral Science Foundation(Grant No.2023TQ0296)the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20232389)Y.Xie acknowledges the support of National Natural Science Foundation of China(62074011,62134008)Beijing Outstanding Young Scientist Program(JWZQ20240102009).
文摘Semiconductor optoelectronics devices,capable of converting electrical power into light or conversely light into electrical power in a compact and highly efficient manner represent one of the most advanced technologies ever developed,which has profoundly reshaped the modern life with a wide range of applications.In recent decades,semiconductor technology has rapidly evolved from first-generation narrow bandgap materials(Si,Ge)to the latest fourth-generation ultra-wide bandgap semiconductor(GaO,diamond,AlN)with enhanced performance to meet growing demands.Additionally,merging semiconductor devices with other techniques,such as computer assisted design,state-of-the-art micro/nano fabrications,novel epitaxial growth,have significantly accelerated the development of semiconductor optoelectronics devices.Among them,integrating metasurfaces with semiconductor optoelectronic devices have opened new frontiers for on-chip control of their electromagnetic response,providing access to previously inaccessible degrees of freedom.We review the recent advances in on-chip control of a variety of semiconductor optoelectronic devices using integrated metasurfaces,including semiconductor lasers,semiconductor light emitting devices,semiconductor photodetectors,and low dimensional semiconductors.The integration of metasurfaces with semiconductors offers wafer-level ultracompact solutions for manipulating the functionalities of semiconductor devices,while also providing a practical platform for implementing cuttingedge metasurface technology in real-world applications.
基金Project supported by the National Natural Science Foundation of China(Nos.U21A20430 and 12302202)the Hebei Natural Science Foundation of China(No.A2023210040)+1 种基金the Science and Technology Project of Hebei Education Department of China(No.BJ2025005)the Hebei Provincial Department of Human Resources and Social Security of China(No.C20220324)。
文摘In this paper,we theoretically study the Lamb wave in a multilayered piezoelectric semiconductor(PSC)plate,where each layer is an n-type PSC with the symmetry of transverse isotropy.Based on the extended Stroh formalism and dual-variable and position(DVP)method,the general solution of the coupled fields for the Lamb wave is derived,and then the dispersion equation is obtained by the application of the boundary conditions.First,the influence of semiconducting properties on the dispersion behavior of the Lamb wave in a single-layer PSC plate is analyzed.Then,the propagation characteristics of the Lamb wave in a sandwich plate are investigated in detail.The numerical results show that the wave speed and attenuation depend on the stacking sequence,layer thickness,and initial carrier density,the Lamb wave can propagate without a cut-off frequency in both the homogeneous and multilayer PSC plates due to the semiconducting properties,and the Lamb wave without attenuation can be achieved by carefully selecting the semiconductor property in the upper and lower layers.These new features could be very helpful as theoretical guidance for the design and performance optimization of PSC devices.
基金supported by the National Key Research and Development Program of China(2022YFB3605902)the National Natural Science Foundation of China(52375411,52293402)。
文摘Workpiece rotational grinding is widely used in the ultra-precision machining of hard and brittle semiconductor materials,including single-crystal silicon,silicon carbide,and gallium arsenide.Surface roughness and subsurface damage depth(SDD)are crucial indicators for evaluating the surface quality of these materials after grinding.Existing prediction models lack general applicability and do not accurately account for the complex material behavior under grinding conditions.This paper introduces novel models for predicting both surface roughness and SDD in hard and brittle semiconductor materials.The surface roughness model uniquely incorporates the material’s elastic recovery properties,revealing the significant impact of these properties on prediction accuracy.The SDD model is distinguished by its analysis of the interactions between abrasive grits and the workpiece,as well as the mechanisms governing stress-induced damage evolution.The surface roughness model and SDD model both establish a stable relationship with the grit depth of cut(GDC).Additionally,we have developed an analytical relationship between the GDC and grinding process parameters.This,in turn,enables the establishment of an analytical framework for predicting surface roughness and SDD based on grinding process parameters,which cannot be achieved by previous models.The models were validated through systematic experiments on three different semiconductor materials,demonstrating excellent agreement with experimental data,with prediction errors of 6.3%for surface roughness and6.9%for SDD.Additionally,this study identifies variations in elastic recovery and material plasticity as critical factors influencing surface roughness and SDD across different materials.These findings significantly advance the accuracy of predictive models and broaden their applicability for grinding hard and brittle semiconductor materials.
基金supported by the National Natural Science Foundation of China(Grant No.12105210)the Knowledge Innovation Program of Wuhan-Basi Research(Grant No.2023010201010149)。
文摘We present a theoretical scheme to realize two-dimensional(2D)asymmetric diffraction grating in a five-level inverted Y-type asymmetric double semiconductor quantum wells(SQWs)structure with resonant tunneling.The SQW structure interacts with a weak probe laser field,a spatially independent 2D standing-wave(SW)field,and a Laguerre–Gaussian(LG)vortex field,respectively.The results indicate that the diffraction patterns are highly sensitive to amplitude modulation and phase modulation.Because of the existence of vortex light,it is possible to realize asymmetric high-order diffraction in the SQW structure,and then a 2D asymmetric grating is established.By adjusting the detunings of the probe field,vortex field,and SW field,as well as the interaction length,diffraction intensity,and direction of the 2D asymmetric electromagnetically induced grating(EIG)can be controlled effectively.In addition,the number of orbital angular momenta(OAM)and beam waist parameter can be used to modulate the diffraction intensity and energy transfer of the probe light in different regions.High-order diffraction intensity is enhanced and high-efficiency 2D asymmetric diffraction grating with different diffraction patterns is obtained in the scheme.Such 2D asymmetric diffraction grating may be beneficial to the research of optical communication and innovative semiconductor quantum devices.
基金Supported by Bissell Distinguished Professor Endowment Fund at UNC-Charlotte。
文摘Although there are numerous optical spectroscopy techniques and methods that have been used to extract the fundamental bandgap of a semiconductor,most of them belong to one of these three approaches:(1)the excitonic absorption,(2)modulation spectroscopy,and(3)the most widely used Tauc-plot.The excitonic absorption is based on a many-particle theory,which is physically the most correct approach,but requires more stringent crystalline quality and appropriate sample preparation and experimental implementation.The Tauc-plot is based on a single-particle theo⁃ry that neglects the many-electron effects.Modulation spectroscopy analyzes the spectroscopy features in the derivative spectrum,typically,of the reflectance and transmission under an external perturbation.Empirically,the bandgap ener⁃gy derived from the three approaches follow the order of E_(ex)>E_(MS)>E_(TP),where three transition energies are from exci⁃tonic absorption,modulation spectroscopy,and Tauc-plot,respectively.In principle,defining E_(g) as the single-elec⁃tron bandgap,we expect E_(g)>E_(ex),thus,E_(g)>E_(TP).In the literature,E_(TP) is often interpreted as E_(g),which is conceptual⁃ly problematic.However,in many cases,because the excitonic peaks are not readily identifiable,the inconsistency be⁃tween E_(g) and E_(TP) becomes invisible.In this brief review,real world examples are used(1)to illustrate how excitonic absorption features depend sensitively on the sample and measurement conditions;(2)to demonstrate the differences between E_(ex),E_(MS),and E_(TP) when they can be extracted simultaneously for one sample;and(3)to show how the popular⁃ly adopted Tauc-plot could lead to misleading results.Finally,it is pointed out that if the excitonic absorption is not ob⁃servable,the modulation spectroscopy can often yield a more useful and reasonable bandgap than Tauc-plot.
文摘Radiation doses to patients in diagnostics and interventional radiology need to be optimized to comply with the principles of radiation protection in medical practice. This involves using specific detectors with respective diagnostic beams to carry out quality control/quality assurance tests needed to optimize patient doses in the hospital. Semiconductor detectors are used in dosimetry to verify the equipment performance and dose to patients. This work aims to assess the performance, energy dependence, and response of five commercially available semiconductor detectors in RQR, RQR-M, RQA, and RQT at Secondary Standard Dosimetry for clinical applications. The diagnostic beams were generated using Exradin A4 reference ion chamber and PTW electrometer. The ambient temperature and pressure were noted for KTP correction. The detectors designed for RQR showed good performance in RQT beams and vice versa. The detectors designed for RQR-M displayed high energy dependency in other diagnostic beams. The type of diagnostic beam quality determines the response of semiconductor detectors. Therefore, a detector should be calibrated according to the beam qualities to be measured.
