Near-infrared(NIR)organic photodetectors(OPDs)hold enormous commercial potential in wearable biosensing and imaging applications.However,their sensi-tivity remains comparatively lower than that of commercially availab...Near-infrared(NIR)organic photodetectors(OPDs)hold enormous commercial potential in wearable biosensing and imaging applications.However,their sensi-tivity remains comparatively lower than that of commercially available silicon-based photodetectors(Si PDs).In this study,we present highly sensitive NIR OPDs by incorporating an all-fused-ring small molecule acceptor,FM4,with low trap den-sity into a conventional active layer system.FM4 effectively reduces traps in the active layer,resulting in a decrease in trap density from 1.57×10^(15)to 8.86×10^(14)cm^(−3).Consequently,under−1 V bias,the OPD device with FM4 as the third component achieves an ultra-low real-measured noise current of 7.56×10^(−15)A Hz^(−1/2)at 1 kHz,lower than that of com-mercial Si PDs,which is primarily attributed to the substantial decrease in trap density within the active layer.Due to its ultra-low noise current,the ternary device exhibits a high specific detectivity of 1.83×10^(13)Jones at 840 nm under−1 V bias and a broad linear dynamic range of 155 dB.Its sensitivity exceeds that of Si PDs.Furthermore,this sensitive OPD device has been successfully utilized in single-pixel low-light imaging,delivering superior image clarity compared to Si PDs.展开更多
We reported the influence of interface trap density（Nt） on the electrical properties of amorphous InSnZnO based thin-film transistors,which were fabricated at different direct-current（DC） magnetron sputtering powe...We reported the influence of interface trap density（Nt） on the electrical properties of amorphous InSnZnO based thin-film transistors,which were fabricated at different direct-current（DC） magnetron sputtering powers.The device with the smallest Nt of 5.68×10^11 cm^-2 and low resistivity of 1.21×10^-3Ω·cm exhibited a turn-on voltage（V（ON）） of-3.60 V,a sub-threshold swing（S.S） of 0.16 V/dec and an on-off ratio（I（ON）/I（OFF）） of^8 x 10^8.With increasing Nt,the V（ON）,S.S and I（ON）/I（OFF） were suppressed to-9.40 V,0.24 V/dec and 2.59×10^8,respectively.The V（TH） shift under negative gate bias stress has also been estimated to investigate the electrical stability of the devices.The result showed that the reduction in Nt contributes to an improvement in the electrical properties and stability.展开更多
Determining the trap density in the absorbing layer thin film of perovskite solar cells is a critically important task,as it directly influences the efficiency of the devices.Here,we proposed time-resolved photolumine...Determining the trap density in the absorbing layer thin film of perovskite solar cells is a critically important task,as it directly influences the efficiency of the devices.Here,we proposed time-resolved photoluminescence(TRPL)as a nondestructive method to assess trap density.A model was constructed to investigate carrier recombination and transition in perovskite materials.The model was utilized for numerical calculations and successfully fitted TRPL signals of perovskite materials.Furthermore,a genetic algorithm was employed to optimize the parameters.Finally,statistical methods were applied to obtain the parameters associated with the trap states of the material.This approach facilitates the successful determination of trap densities for different samples with clear differentiation.展开更多
The distributions of traps and electron density in the interfaces between polyimide （PI） matrix and Al2O3 nanoparticles are researched using the isothermal decay current and the small-angle x-ray scattering （SAXS）...The distributions of traps and electron density in the interfaces between polyimide （PI） matrix and Al2O3 nanoparticles are researched using the isothermal decay current and the small-angle x-ray scattering （SAXS） tests. According to the electron density distribution for quasi two-phase mixture doped by spherical nanoparticles, the electron densities in the interfaces of PI/Al2O3 nanocomposite films are evaluated. The trap level density and carrier mobility in the interface are studied. The experimental results show that the distribution and the change rate of the electron density in the three layers of interface are different, indicating different trap distributions in the interface layers. There is a maximum trap level density in the second layer, where the maximum trap level density for the nanocomposite film doped by 25 wt% is 1.054 × 10^22 eV·m^-3 at 1.324eV, resulting in the carrier mobility reducing. In addition, both the thickness and the electron density of the nanocomposite film interface increase with the addition of the doped Al2O3 contents. Through the study on the trap level distribution in the interface, it is possible to further analyze the insulation mechanism and to improve the performance of nano-dielectric materials.展开更多
Charge trap density and carrier mobility of perovskite materials are the critical properties of perovskite solar cells.The space charge limited current(SCLC)method,which measures a dark current–voltage(I-V)curve of a...Charge trap density and carrier mobility of perovskite materials are the critical properties of perovskite solar cells.The space charge limited current(SCLC)method,which measures a dark current–voltage(I-V)curve of a single-carrier device has found extensive use for studying the trap density and charge carrier mobility in perovskite materials.Herein,it was found that the electron-and hole-current in organo-lead perovskite-based single-carrier device undergoes significant hysteresis under forward and reverse scanning due to the mobile ions.In addition,it was also observed that measuring history has a detrimental effect on hysteresis resulting in possible overestimation or underestimation of the extracted electrical values from the SCLC measurement.In the forward/reverse scanning process,the mobile ionic defects enhance/shield the charge in the traps due to ionic charging/discharging,thereby increasing/reducing the interface barrier and net charge in the I-V scanning,which in turn affects the determination of transport properties of the carrier.These results raise quite a few doubts over the direct application of classical SCLC measurements for the accurate characterization of intrinsic transport properties of the mixed ionicelectronic perovskite.展开更多
An investigation is carried out for understanding the properties of ion–acoustic（IA） solitary waves in an inhomogeneous magnetized electron-ion plasma with field-aligned sheared flow under the impact of q-nonextens...An investigation is carried out for understanding the properties of ion–acoustic（IA） solitary waves in an inhomogeneous magnetized electron-ion plasma with field-aligned sheared flow under the impact of q-nonextensive trapped electrons. The Schamel equation and its stationary solution in the form of solitary waves are obtained for this inhomogeneous plasma. It is shown that the amplitude of IA solitary waves increases with higher trapping efficiency（β）, while the width remains almost the same. Further, it is found that the amplitude of the solitary waves decreases with enhanced normalized drift speed, shear flow parameter and the population of the energetic particles. The size of the nonlinear solitary structures is calculated to be a few hundred meters and it is pointed out that the present results are useful to understand the solar wind plasma.展开更多
Ideal nanoscale phase-separated morphology is the primary condition to obtain high photovoltaic conversion efficiency(PCE)and high stability of organic solar cells(OSCs).However,the differences in solubility,miscibili...Ideal nanoscale phase-separated morphology is the primary condition to obtain high photovoltaic conversion efficiency(PCE)and high stability of organic solar cells(OSCs).However,the differences in solubility,miscibility and crystallinity between donors and acceptors make it difficult to achieve the optimal active layer morphology of OSCs.Herein,the volatile solid additive 3,5-dibromotoluene(DTL)with strong electronegativity and dipole moment has been developed for OSCs.DTL can interact with the acceptor,modulating its crystallization and stacking,enhancing donor/acceptor miscibility,reducing trap density,inhibiting carrier recombination,and balancing charge transport.Notably,the introduction of DTL finely tunes the energy level of the accepto r,which greatly enhances the open-circuit voltage(V_(OC))of the device compared to the conventional additive 1,8-diiodooctane(DIO).As a result,the DTL-treated PM6:L8-BObased OSCs obtained a high PCE of 18.87%and enhanced stability.Furthermore,the PM6:PM1:L8-BO+DTL-based OSCs achieved a champion PCE of 19.11%.This work deepens the working mechanism of additive strategy for regulating the morphology and improving performance,providing an effective method for achieving high-performance OSCs.展开更多
In the sentence beginning'and more irreversible hydrogentrapping sites….'in this article,the value'0.38×1025 cm-3'should have read'0.68×1020 cm-3'.These corrections do not alter the ...In the sentence beginning'and more irreversible hydrogentrapping sites….'in this article,the value'0.38×1025 cm-3'should have read'0.68×1020 cm-3'.These corrections do not alter the primary conclusion that the irreversible hydrogen trap density in 42CrNiMoV steel is nearly twice that of 40CrNiMo steel.展开更多
The metal oxides with low trap density of states as the electron transport layer are crucial for the high performance of the organic solar cells(OSCs).It is universally acknowledged that modifying n-type metal oxide c...The metal oxides with low trap density of states as the electron transport layer are crucial for the high performance of the organic solar cells(OSCs).It is universally acknowledged that modifying n-type metal oxide contacts with polymer donors will harm the carrier extraction on account of the mismatched energy level.However,we find that modifying interlayer consisting of the alcohol amines with some polymer donor additive can unusually enhance the performance of the OSCs.Compared with triethanolamine(TEA)passivated ZnO,TEA:polymer donor treated ZnO shows lower trap density and enhances electron mobility resulting in higher current density in OSC devices.Here,we reveal that the enhanced oxygen-defect passivation ability of TEA with polymer additive is attributed to the enhanced negative electrostatic potential of TEA owing to the hydrogen bond formation between the polymer and the hydroxyl group in TEA.This strategy that enhancing the negative electrostatic potential of the passivators for improving oxygen defect passivation can be extended to other types of organic electronic devices.展开更多
Nitrogen plasma passivation （NPP） on （111） germanium （Ge） was studied in terms of the interface trap density, roughness, and interfacial layer thickness using plasma-enhanced chemical vapor deposition （PECVD）....Nitrogen plasma passivation （NPP） on （111） germanium （Ge） was studied in terms of the interface trap density, roughness, and interfacial layer thickness using plasma-enhanced chemical vapor deposition （PECVD）. The results show that NPP not only reduces the interface states, but also improves the surface roughness of Ge, which is beneficial for suppressing the channel scattering at both low and high field regions of Ge MOSFETs. However, the interracial layer thickness is also increased by the NPP treatment, which will impact the equivalent oxide thickness （EOT） scaling and thus degrade the device performance gain from the improvement of the surface morphology and the interface passivation. To obtain better device performance of Ge MOSFETs, suppressing the interfacial layer regrowth as well as a trade-off with reducing the interface states and roughness should be considered carefully when using the NPP process.展开更多
ZnO-based thin film transistors(TFTs)with high bias stability are challenging due to the intrinsic defects and overhigh interface trap density.In this work,we fabricated Hf-doped ZnO films with different cycle ratio o...ZnO-based thin film transistors(TFTs)with high bias stability are challenging due to the intrinsic defects and overhigh interface trap density.In this work,we fabricated Hf-doped ZnO films with different cycle ratio of Zn/Hf via atomic layer deposition and subsequent annealing treatment.The results show that the cycle ratio of Zn/Hf is optimized to be 10:1,and the corresponding atomic ratio is 2.24%.The threshold voltage and subthreshold swing of the devices are improved as the annealing temperature increases,owning to the decrease of the oxygen vacancies and interface trap density.Furthermore,we developed Hf-doped ZnO TFT with high bias stability by introducing HfO_(2)intermediate layer between the active layer and SiO_(2)dielectric layer,and the shift of threshold voltage is as low as-0.273 V,showing high bias stability.Also,the device has the high field-effective mobility of 52.4 cm^(2)/Vs,low subthreshold swing of 0.68 V/dec and high Ion/Ioff of 3.6×10^(8).The results indicate a promising fabrication method for highperformance ZnO-based TFTs,which may be applied in logic circuits,radio frequency identification and so on.展开更多
The thickness effect of the TiN capping layer on the time dependent dielectric breakdown（TDDB） characteristic of ultra-thin EOT high-k metal gate NMOSFET is investigated in this paper.Based on experimental results,i...The thickness effect of the TiN capping layer on the time dependent dielectric breakdown（TDDB） characteristic of ultra-thin EOT high-k metal gate NMOSFET is investigated in this paper.Based on experimental results,it is found that the device with a thicker TiN layer has a more promising reliability characteristic than that with a thinner TiN layer.From the charge pumping measurement and secondary ion mass spectroscopy（SIMS） analysis,it is indicated that the sample with the thicker TiN layer introduces more Cl passivation at the IL/Si interface and exhibits a lower interface trap density.In addition,the influences of interface and bulk trap density ratio Nit/Not are studied by TDDB simulations through combining percolation theory and the kinetic Monte Carlo（kMC） method.The lifetime reduction and Weibull slope lowering are explained by interface trap effects for TiN capping layers with different thicknesses.展开更多
AHfO2/n–In Al As MOS-capacitor has the advantage of reducing the serious gate leakage current when it is adopted in In As/Al Sb HEMT instead of the conventional Schottky-gate. In this paper, three kinds of Hf O2/n–I...AHfO2/n–In Al As MOS-capacitor has the advantage of reducing the serious gate leakage current when it is adopted in In As/Al Sb HEMT instead of the conventional Schottky-gate. In this paper, three kinds of Hf O2/n–InAlAs MOS-capacitor samples with different Hf O2 thickness values of 6, 8, and 10 nm are fabricated and used to investigate the interfacial and electrical characteristics. As the thickness is increased, the equivalent dielectric constant ε ox of Hf O2 layer is enhanced and the In AlAsHfO2 interface trap density Ditis reduced, leading to an effective reduction of the leakage current. It is found that the Hf O2 thickness of 10 nm is a suitable value to satisfy the demands of most applications of a HfO2/n–InAlAs MOS-capacitor, with a sufficiently low leakage current compromised with the threshold voltage.展开更多
The interfacial characteristics of Al/Al2O3/ZnO/n-GaAs metal-oxide-semiconductor （MOS） capacitor are investigated. The results measured by X-ray photoelectron spectroscopy （XPS） and high-resolution transmission el...The interfacial characteristics of Al/Al2O3/ZnO/n-GaAs metal-oxide-semiconductor （MOS） capacitor are investigated. The results measured by X-ray photoelectron spectroscopy （XPS） and high-resolution transmission electron microscopy （HRTEM） show that the presence of ZnO can effectively suppress the formations of oxides at the interface between the GaAs and gate dielectric and gain smooth interface. The ZnO-passivated GaAs MOS capacitor exhibits a very small hysteresis and frequency dispersion. Using the Terman method, the interface trap density is extracted from C-V curves. It is found that the ZnO layer can effectively improve the interface quality.展开更多
We studied the trapping effects on Ostrinia furnacalis from the aspects of different hanging heights and different color traps. The results suggested that the hanging height of 1.5 - 2.0 m received a better trapping e...We studied the trapping effects on Ostrinia furnacalis from the aspects of different hanging heights and different color traps. The results suggested that the hanging height of 1.5 - 2.0 m received a better trapping effect, but trap color had little impact on trapping effect. The sex pheromone traps at different densities were placed in corn field. The results showed that sex pheromone lure could trap adult O. furnacalis, and it was feasible to apply sex pheromone in short term fore- cast. Meanwhile, it reduced the number of larvae and eggs, thereby reducing the damage of O. furnacalis. The lure number of 10 per hm2 was more appropriate, which could result in increasing yield of 8.61% compared with control展开更多
Ever since its mid nineteenth century inauguration, the logistic function and its numerous applications have received a great deal of attention from engineers, and natural and social scientists. In particular, its dis...Ever since its mid nineteenth century inauguration, the logistic function and its numerous applications have received a great deal of attention from engineers, and natural and social scientists. In particular, its discrete relative, the logistic map, has proven to be a principal and indispensable tool of scientists in their effort to describe the dynamics of a variety of physical and biological systems. Our purpose in this paper is to describe one such application, namely, photoconductivity under pulsed excitation and show that the solution of the energy-independent kinetic rate equation for electron density can be expressed as a logistic map.展开更多
On the basis of thermodynamic and kinetic consideration of Ge-O system,high-pressure oxidation(HPO)on Ge was proposed to suppress the GeO desorption during the thermal oxidation and significant improvements of Ge/GeO2...On the basis of thermodynamic and kinetic consideration of Ge-O system,high-pressure oxidation(HPO)on Ge was proposed to suppress the GeO desorption during the thermal oxidation and significant improvements of Ge/GeO2-based gate stacks have been achieved.It is found that the post oxidation annealing at lower temperatures is helpful to passivate the interface defects at the Ge/GeO2 stack generated by the conventional thermal oxidation,while the high-quality GeO2 bulk properties can only be achieved by HPO that grows GeO2 film at high temperatures without the GeO desorption.This paper reviews the advantage of HPO on the formation of Ge/GeO2 stacks in terms of Ge/GeO2 interface and GeO2 bulk properties.展开更多
Two-dimensional(2D)perovskites solar cells(PSCs)have attracted considerable attention owing to their excellent stability against humidity;however,some imperfectness of 2D perovskites,such as poor crystallinity,disorde...Two-dimensional(2D)perovskites solar cells(PSCs)have attracted considerable attention owing to their excellent stability against humidity;however,some imperfectness of 2D perovskites,such as poor crystallinity,disordered orientation,and inferior charge transport still limit the power conversion efficiency(PCE)of 2D PSCs.In this work,2D Ti3C2Tx MXene nanosheets with high electrical conductivity and mobility were employed as a nanosized additive to prepare 2D Ruddlesden–Popper perovskite films.The PCE of solar cells was increased from 13.69(without additive)to 15.71%after incorporating the Ti_(3)C_(2)T_(x) nanosheets with an optimized concentration.This improved performance is attributed to the enhanced crystallinity,orientation,and passivated trap states in the 3D phase that result in accelerated charge transfer process in vertical direction.More importantly,the unencapsulated cells exhibited excellent stability under ambient conditions with 55±5%relative humidity.展开更多
In this work,grain boundary(GB)potential barrier(ΔφGB),dopant density(Pnet),and filled trap state density(PGB,trap)were manipulated at the nanoscale by exposing the fabricated perovskite films to various relative hu...In this work,grain boundary(GB)potential barrier(ΔφGB),dopant density(Pnet),and filled trap state density(PGB,trap)were manipulated at the nanoscale by exposing the fabricated perovskite films to various relative humidity(RH)environments.Spatial mapping of surface potential in the perovskite film revealed higher positive potential at GBs than inside the grains.The averageΔφGB,Pnet,and PGB,trap in the perovskite films decreased from 0%RH to 25%RH exposure,but increased when the RH increased to 35%RH and 45%RH.This clearly indicated that perovskite solar cells fabricated at 25%RH led to the lowest average GB potential,smallest dopant density,and least filled trap states density.This is consistent with the highest photovoltaic efficiency of 18.16%at 25%RH among the different relative humidities from 0%to 45%RH.展开更多
Organic semiconductor materials possess unique advantages in various photoelectric applications.Due to the complicated preparation processes,many impurities are difficult to remove and become extrinsic traps in materi...Organic semiconductor materials possess unique advantages in various photoelectric applications.Due to the complicated preparation processes,many impurities are difficult to remove and become extrinsic traps in materials.However,there exists almost no relevant research on the effects of extrinsic traps on the performance of organic semiconductor materials.In this work,we comprehensively investigate the impacts of ionic traps based on organic photovoltaic(OPV)cells.We demonstrate that the different effects of impurities result from their ionization ability in processing solvent.The ionic traps can induce increased density of trap states and severe trapassist recombination,thereby deteriorating device performance.In addition,we propose a simple method to evaluate the quality of organic semiconductor materials through electrochemical impedance spectroscopy.This research facilitates the batch preparation of organic semiconductor materials and the industrialization of OPV cells.展开更多
基金financially supported by the National Natural Science Foundation of China (U24A2080 and 22135007)the CAS Project for Young Scientists in Basic Research (YSBR-110)。
文摘Near-infrared(NIR)organic photodetectors(OPDs)hold enormous commercial potential in wearable biosensing and imaging applications.However,their sensi-tivity remains comparatively lower than that of commercially available silicon-based photodetectors(Si PDs).In this study,we present highly sensitive NIR OPDs by incorporating an all-fused-ring small molecule acceptor,FM4,with low trap den-sity into a conventional active layer system.FM4 effectively reduces traps in the active layer,resulting in a decrease in trap density from 1.57×10^(15)to 8.86×10^(14)cm^(−3).Consequently,under−1 V bias,the OPD device with FM4 as the third component achieves an ultra-low real-measured noise current of 7.56×10^(−15)A Hz^(−1/2)at 1 kHz,lower than that of com-mercial Si PDs,which is primarily attributed to the substantial decrease in trap density within the active layer.Due to its ultra-low noise current,the ternary device exhibits a high specific detectivity of 1.83×10^(13)Jones at 840 nm under−1 V bias and a broad linear dynamic range of 155 dB.Its sensitivity exceeds that of Si PDs.Furthermore,this sensitive OPD device has been successfully utilized in single-pixel low-light imaging,delivering superior image clarity compared to Si PDs.
文摘We reported the influence of interface trap density（Nt） on the electrical properties of amorphous InSnZnO based thin-film transistors,which were fabricated at different direct-current（DC） magnetron sputtering powers.The device with the smallest Nt of 5.68×10^11 cm^-2 and low resistivity of 1.21×10^-3Ω·cm exhibited a turn-on voltage（V（ON）） of-3.60 V,a sub-threshold swing（S.S） of 0.16 V/dec and an on-off ratio（I（ON）/I（OFF）） of^8 x 10^8.With increasing Nt,the V（ON）,S.S and I（ON）/I（OFF） were suppressed to-9.40 V,0.24 V/dec and 2.59×10^8,respectively.The V（TH） shift under negative gate bias stress has also been estimated to investigate the electrical stability of the devices.The result showed that the reduction in Nt contributes to an improvement in the electrical properties and stability.
基金supported by the National Natural Science Foundation of China(Nos.62104234 and 52103279)the Shanghai Sailing Program(No.21YF1454000)。
文摘Determining the trap density in the absorbing layer thin film of perovskite solar cells is a critically important task,as it directly influences the efficiency of the devices.Here,we proposed time-resolved photoluminescence(TRPL)as a nondestructive method to assess trap density.A model was constructed to investigate carrier recombination and transition in perovskite materials.The model was utilized for numerical calculations and successfully fitted TRPL signals of perovskite materials.Furthermore,a genetic algorithm was employed to optimize the parameters.Finally,statistical methods were applied to obtain the parameters associated with the trap states of the material.This approach facilitates the successful determination of trap densities for different samples with clear differentiation.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51337002,51077028,51502063 and 51307046the Foundation of Harbin Science and Technology Bureau of Heilongjiang Province under Grant No RC2014QN017034
文摘The distributions of traps and electron density in the interfaces between polyimide （PI） matrix and Al2O3 nanoparticles are researched using the isothermal decay current and the small-angle x-ray scattering （SAXS） tests. According to the electron density distribution for quasi two-phase mixture doped by spherical nanoparticles, the electron densities in the interfaces of PI/Al2O3 nanocomposite films are evaluated. The trap level density and carrier mobility in the interface are studied. The experimental results show that the distribution and the change rate of the electron density in the three layers of interface are different, indicating different trap distributions in the interface layers. There is a maximum trap level density in the second layer, where the maximum trap level density for the nanocomposite film doped by 25 wt% is 1.054 × 10^22 eV·m^-3 at 1.324eV, resulting in the carrier mobility reducing. In addition, both the thickness and the electron density of the nanocomposite film interface increase with the addition of the doped Al2O3 contents. Through the study on the trap level distribution in the interface, it is possible to further analyze the insulation mechanism and to improve the performance of nano-dielectric materials.
基金supported in part by the National Natural Science Foundation of China(6200406821607041+4 种基金12147219)the Zhejiang Provincial Natural Science Foundation of China(Y20F040001)the Natural Science Foundation of Huzhou City,China(2019YZ02)the Syracuse University Startup Fundthe U.S.-Egypt Science and Technology(S&T)Joint Fund。
文摘Charge trap density and carrier mobility of perovskite materials are the critical properties of perovskite solar cells.The space charge limited current(SCLC)method,which measures a dark current–voltage(I-V)curve of a single-carrier device has found extensive use for studying the trap density and charge carrier mobility in perovskite materials.Herein,it was found that the electron-and hole-current in organo-lead perovskite-based single-carrier device undergoes significant hysteresis under forward and reverse scanning due to the mobile ions.In addition,it was also observed that measuring history has a detrimental effect on hysteresis resulting in possible overestimation or underestimation of the extracted electrical values from the SCLC measurement.In the forward/reverse scanning process,the mobile ionic defects enhance/shield the charge in the traps due to ionic charging/discharging,thereby increasing/reducing the interface barrier and net charge in the I-V scanning,which in turn affects the determination of transport properties of the carrier.These results raise quite a few doubts over the direct application of classical SCLC measurements for the accurate characterization of intrinsic transport properties of the mixed ionicelectronic perovskite.
文摘An investigation is carried out for understanding the properties of ion–acoustic（IA） solitary waves in an inhomogeneous magnetized electron-ion plasma with field-aligned sheared flow under the impact of q-nonextensive trapped electrons. The Schamel equation and its stationary solution in the form of solitary waves are obtained for this inhomogeneous plasma. It is shown that the amplitude of IA solitary waves increases with higher trapping efficiency（β）, while the width remains almost the same. Further, it is found that the amplitude of the solitary waves decreases with enhanced normalized drift speed, shear flow parameter and the population of the energetic particles. The size of the nonlinear solitary structures is calculated to be a few hundred meters and it is pointed out that the present results are useful to understand the solar wind plasma.
基金supported by the National Natural Science Foundation of China(NSFC Grant Nos.62075029,52130304,62105055,62222503,62474028 and 52073040)The Fundamental Research Funds for the Central Universities(Program No.ZYGX2021J017)+5 种基金Sichuan Provincial Regional Innovation Cooperation Project(Program No.2022YFQ0078)Creative Research Groups of the National Natural Science Foundation of Sichuan Province(2023NSFSC1973)The Sichuan Science and Technology Program(Grant No.2024NSFSC0012,2024NSFSC1447)The Sichuan Science and Technology Program(Grant Nos.2024NSFSC1446)National Key R and D Program of China(2023YFB2604101)The China Postdoctoral Science Foundation(Grant Nos.2023M740504,GZC20230380)。
文摘Ideal nanoscale phase-separated morphology is the primary condition to obtain high photovoltaic conversion efficiency(PCE)and high stability of organic solar cells(OSCs).However,the differences in solubility,miscibility and crystallinity between donors and acceptors make it difficult to achieve the optimal active layer morphology of OSCs.Herein,the volatile solid additive 3,5-dibromotoluene(DTL)with strong electronegativity and dipole moment has been developed for OSCs.DTL can interact with the acceptor,modulating its crystallization and stacking,enhancing donor/acceptor miscibility,reducing trap density,inhibiting carrier recombination,and balancing charge transport.Notably,the introduction of DTL finely tunes the energy level of the accepto r,which greatly enhances the open-circuit voltage(V_(OC))of the device compared to the conventional additive 1,8-diiodooctane(DIO).As a result,the DTL-treated PM6:L8-BObased OSCs obtained a high PCE of 18.87%and enhanced stability.Furthermore,the PM6:PM1:L8-BO+DTL-based OSCs achieved a champion PCE of 19.11%.This work deepens the working mechanism of additive strategy for regulating the morphology and improving performance,providing an effective method for achieving high-performance OSCs.
文摘In the sentence beginning'and more irreversible hydrogentrapping sites….'in this article,the value'0.38×1025 cm-3'should have read'0.68×1020 cm-3'.These corrections do not alter the primary conclusion that the irreversible hydrogen trap density in 42CrNiMoV steel is nearly twice that of 40CrNiMo steel.
基金This work was financially supported by the National Natural Science Foundation of China(No.52173189).
文摘The metal oxides with low trap density of states as the electron transport layer are crucial for the high performance of the organic solar cells(OSCs).It is universally acknowledged that modifying n-type metal oxide contacts with polymer donors will harm the carrier extraction on account of the mismatched energy level.However,we find that modifying interlayer consisting of the alcohol amines with some polymer donor additive can unusually enhance the performance of the OSCs.Compared with triethanolamine(TEA)passivated ZnO,TEA:polymer donor treated ZnO shows lower trap density and enhances electron mobility resulting in higher current density in OSC devices.Here,we reveal that the enhanced oxygen-defect passivation ability of TEA with polymer additive is attributed to the enhanced negative electrostatic potential of TEA owing to the hydrogen bond formation between the polymer and the hydroxyl group in TEA.This strategy that enhancing the negative electrostatic potential of the passivators for improving oxygen defect passivation can be extended to other types of organic electronic devices.
基金supported by the National Basic Research Program of China(Grant No.2011CBA00601)the National Science and Technology Major Project of the Ministry of Science and Technology of China(Grant No.2009ZX02035-001)the National Natural Science Foundation of China(Grant Nos.60625403,60806033,and 60925015)
文摘Nitrogen plasma passivation （NPP） on （111） germanium （Ge） was studied in terms of the interface trap density, roughness, and interfacial layer thickness using plasma-enhanced chemical vapor deposition （PECVD）. The results show that NPP not only reduces the interface states, but also improves the surface roughness of Ge, which is beneficial for suppressing the channel scattering at both low and high field regions of Ge MOSFETs. However, the interracial layer thickness is also increased by the NPP treatment, which will impact the equivalent oxide thickness （EOT） scaling and thus degrade the device performance gain from the improvement of the surface morphology and the interface passivation. To obtain better device performance of Ge MOSFETs, suppressing the interfacial layer regrowth as well as a trade-off with reducing the interface states and roughness should be considered carefully when using the NPP process.
基金the National Key R&D Program of China(No.2020YFB2008701)。
文摘ZnO-based thin film transistors(TFTs)with high bias stability are challenging due to the intrinsic defects and overhigh interface trap density.In this work,we fabricated Hf-doped ZnO films with different cycle ratio of Zn/Hf via atomic layer deposition and subsequent annealing treatment.The results show that the cycle ratio of Zn/Hf is optimized to be 10:1,and the corresponding atomic ratio is 2.24%.The threshold voltage and subthreshold swing of the devices are improved as the annealing temperature increases,owning to the decrease of the oxygen vacancies and interface trap density.Furthermore,we developed Hf-doped ZnO TFT with high bias stability by introducing HfO_(2)intermediate layer between the active layer and SiO_(2)dielectric layer,and the shift of threshold voltage is as low as-0.273 V,showing high bias stability.Also,the device has the high field-effective mobility of 52.4 cm^(2)/Vs,low subthreshold swing of 0.68 V/dec and high Ion/Ioff of 3.6×10^(8).The results indicate a promising fabrication method for highperformance ZnO-based TFTs,which may be applied in logic circuits,radio frequency identification and so on.
基金supported by the National High Technology Research and Development Program of China(Grant No.SS2015AA010601)the National Natural Science Foundation of China(Grant Nos.61176091 and 61306129)the Opening Project of Key Laboratory of Microelectronics Devices&Integrated Technology,Institute of Micro Electronics of Chinese Academy of Sciences
文摘The thickness effect of the TiN capping layer on the time dependent dielectric breakdown（TDDB） characteristic of ultra-thin EOT high-k metal gate NMOSFET is investigated in this paper.Based on experimental results,it is found that the device with a thicker TiN layer has a more promising reliability characteristic than that with a thinner TiN layer.From the charge pumping measurement and secondary ion mass spectroscopy（SIMS） analysis,it is indicated that the sample with the thicker TiN layer introduces more Cl passivation at the IL/Si interface and exhibits a lower interface trap density.In addition,the influences of interface and bulk trap density ratio Nit/Not are studied by TDDB simulations through combining percolation theory and the kinetic Monte Carlo（kMC） method.The lifetime reduction and Weibull slope lowering are explained by interface trap effects for TiN capping layers with different thicknesses.
基金Project supported by the National Basic Research Program of China(Grant No.2010CB327505)the Advance Research Foundation of China(Grant No.914xxx803-051xxx111)
文摘AHfO2/n–In Al As MOS-capacitor has the advantage of reducing the serious gate leakage current when it is adopted in In As/Al Sb HEMT instead of the conventional Schottky-gate. In this paper, three kinds of Hf O2/n–InAlAs MOS-capacitor samples with different Hf O2 thickness values of 6, 8, and 10 nm are fabricated and used to investigate the interfacial and electrical characteristics. As the thickness is increased, the equivalent dielectric constant ε ox of Hf O2 layer is enhanced and the In AlAsHfO2 interface trap density Ditis reduced, leading to an effective reduction of the leakage current. It is found that the Hf O2 thickness of 10 nm is a suitable value to satisfy the demands of most applications of a HfO2/n–InAlAs MOS-capacitor, with a sufficiently low leakage current compromised with the threshold voltage.
基金the National Basic Research Program of China(Grant No.2010CB327505)the National Defense Advance Research Foundation,China(Grant No.9140A08030511DZ111)the National Defense Advance Research Project,China(Grant No.51308030306)
文摘The interfacial characteristics of Al/Al2O3/ZnO/n-GaAs metal-oxide-semiconductor （MOS） capacitor are investigated. The results measured by X-ray photoelectron spectroscopy （XPS） and high-resolution transmission electron microscopy （HRTEM） show that the presence of ZnO can effectively suppress the formations of oxides at the interface between the GaAs and gate dielectric and gain smooth interface. The ZnO-passivated GaAs MOS capacitor exhibits a very small hysteresis and frequency dispersion. Using the Terman method, the interface trap density is extracted from C-V curves. It is found that the ZnO layer can effectively improve the interface quality.
基金Supported by National Key Technology R&D Program(2011BAD16B10)Supporting Project of National Key Technology R&D Program(2015GJLS001NY)
文摘We studied the trapping effects on Ostrinia furnacalis from the aspects of different hanging heights and different color traps. The results suggested that the hanging height of 1.5 - 2.0 m received a better trapping effect, but trap color had little impact on trapping effect. The sex pheromone traps at different densities were placed in corn field. The results showed that sex pheromone lure could trap adult O. furnacalis, and it was feasible to apply sex pheromone in short term fore- cast. Meanwhile, it reduced the number of larvae and eggs, thereby reducing the damage of O. furnacalis. The lure number of 10 per hm2 was more appropriate, which could result in increasing yield of 8.61% compared with control
文摘Ever since its mid nineteenth century inauguration, the logistic function and its numerous applications have received a great deal of attention from engineers, and natural and social scientists. In particular, its discrete relative, the logistic map, has proven to be a principal and indispensable tool of scientists in their effort to describe the dynamics of a variety of physical and biological systems. Our purpose in this paper is to describe one such application, namely, photoconductivity under pulsed excitation and show that the solution of the energy-independent kinetic rate equation for electron density can be expressed as a logistic map.
基金The author would like to thank Prof.Akira Toriumi,Prof.Kita Koji,Prof.Kosuke Nagashio,and Dr.Tomonori Nishimura at the University of Tokyo for their continuous support and encouragement,which induced the main results reviewed in this paper.
文摘On the basis of thermodynamic and kinetic consideration of Ge-O system,high-pressure oxidation(HPO)on Ge was proposed to suppress the GeO desorption during the thermal oxidation and significant improvements of Ge/GeO2-based gate stacks have been achieved.It is found that the post oxidation annealing at lower temperatures is helpful to passivate the interface defects at the Ge/GeO2 stack generated by the conventional thermal oxidation,while the high-quality GeO2 bulk properties can only be achieved by HPO that grows GeO2 film at high temperatures without the GeO desorption.This paper reviews the advantage of HPO on the formation of Ge/GeO2 stacks in terms of Ge/GeO2 interface and GeO2 bulk properties.
基金the National Natural Science Foundation of China(No.11974129 to X.-F.W.)“the Fundamental Research Funds for the Central Universities,Jilin University.”。
文摘Two-dimensional(2D)perovskites solar cells(PSCs)have attracted considerable attention owing to their excellent stability against humidity;however,some imperfectness of 2D perovskites,such as poor crystallinity,disordered orientation,and inferior charge transport still limit the power conversion efficiency(PCE)of 2D PSCs.In this work,2D Ti3C2Tx MXene nanosheets with high electrical conductivity and mobility were employed as a nanosized additive to prepare 2D Ruddlesden–Popper perovskite films.The PCE of solar cells was increased from 13.69(without additive)to 15.71%after incorporating the Ti_(3)C_(2)T_(x) nanosheets with an optimized concentration.This improved performance is attributed to the enhanced crystallinity,orientation,and passivated trap states in the 3D phase that result in accelerated charge transfer process in vertical direction.More importantly,the unencapsulated cells exhibited excellent stability under ambient conditions with 55±5%relative humidity.
基金This work has been supported in part by NSF MRI(1428992)NASA EPSCoR(NNX15AM83A)+3 种基金U.S.-Egypt Science and Technology(S&T)Joint Fund,SDBoR R&D Program,and EDA University Center Program(ED18DEN3030025)This work is derived from the Subject Data supported in whole or part by NAS and USAID,and any opinions,findings,conclusions,or recommendations expressed in the paper are those of the authors alone,and do not necessarily reflect the views of USAID or NAS.We would like to thank Dr Brian Moore for assisting us with high performance computing facility at South Dakota State University.W.Y.acknowledges the support from International Cooperation Project of Anhui Province(1503062018)Visiting Research Scholar Project for Young/Middle Excellent Talents of Anhui Province(gxfxZD2016110)Preeminent Youth Foundation of Anhui Polytechnic University(2016JQ002).
文摘In this work,grain boundary(GB)potential barrier(ΔφGB),dopant density(Pnet),and filled trap state density(PGB,trap)were manipulated at the nanoscale by exposing the fabricated perovskite films to various relative humidity(RH)environments.Spatial mapping of surface potential in the perovskite film revealed higher positive potential at GBs than inside the grains.The averageΔφGB,Pnet,and PGB,trap in the perovskite films decreased from 0%RH to 25%RH exposure,but increased when the RH increased to 35%RH and 45%RH.This clearly indicated that perovskite solar cells fabricated at 25%RH led to the lowest average GB potential,smallest dopant density,and least filled trap states density.This is consistent with the highest photovoltaic efficiency of 18.16%at 25%RH among the different relative humidities from 0%to 45%RH.
基金supported by National Key Research and Development Program of China(grant no.2022YFF0709900)the National Natural Science Foundation of China(grant no.22322904)support from the Youth Innovation Promotion Association CAS(grant no.2023036).
文摘Organic semiconductor materials possess unique advantages in various photoelectric applications.Due to the complicated preparation processes,many impurities are difficult to remove and become extrinsic traps in materials.However,there exists almost no relevant research on the effects of extrinsic traps on the performance of organic semiconductor materials.In this work,we comprehensively investigate the impacts of ionic traps based on organic photovoltaic(OPV)cells.We demonstrate that the different effects of impurities result from their ionization ability in processing solvent.The ionic traps can induce increased density of trap states and severe trapassist recombination,thereby deteriorating device performance.In addition,we propose a simple method to evaluate the quality of organic semiconductor materials through electrochemical impedance spectroscopy.This research facilitates the batch preparation of organic semiconductor materials and the industrialization of OPV cells.
