The introduction of two-dimensional(2D)perovskite layers on top of three-dimensional(3D)perovskite films enhances the performance and stability of perovskite solar cells(PSCs).However,the electronic effect of the spac...The introduction of two-dimensional(2D)perovskite layers on top of three-dimensional(3D)perovskite films enhances the performance and stability of perovskite solar cells(PSCs).However,the electronic effect of the spacer cation and the quality of the 2D capping layer are critical factors in achieving the required results.In this study,we compared two fluorinated salts:4-(trifluoromethyl)benzamidine hydrochloride(4TF-BA·HCl)and 4-fluorobenzamidine hydrochloride(4F-BA·HCl)to engineer the 3D/2D perovskite films.Surprisingly,4F-BA formed a high-performance 3D/2D heterojunction,while4TF-BA produced an amorphous layer on the perovskite films.Our findings indicate that the balanced intramolecular charge polarization,which leads to effective hydrogen bonding,is more favorable in 4F-BA than in 4TF-BA,promoting the formation of a crystalline 2D perovskite.Nevertheless,4TF-BA managed to improve efficiency to 24%,surpassing the control device,primarily due to the natural passivation capabilities of benzamidine.Interestingly,the devices based on 4F-BA demonstrated an efficiency exceeding 25%with greater longevity under various storage conditions compared to 4TF-BA-based and the control devices.展开更多
Surgical electrodes are frequently associated with disadvantages such as high surface adhesion and severe thermal damage to adjacent normal tissues,which threaten operation quality and patient safety.In this study,by ...Surgical electrodes are frequently associated with disadvantages such as high surface adhesion and severe thermal damage to adjacent normal tissues,which threaten operation quality and patient safety.In this study,by mimicking the micromorphology and bio-anti-adhesion of shark skin,we proposed a strategy that utilized nanoscale aluminium oxide(Al_(2)O_(3))films deposited on bioinspired shark skin(BSS)microstructures to design a composite surface(Al_(2)O_(3)@BSS)and integrated it into both flat sides of the surgical electrodes.Micro/nano-manufacturing of the Al_(2)O_(3)@BSS surface was sequentially accomplished using nanosecond laser texturing,atomic layer deposition,and low-temperature annealing,endowing it with excellent blood-repellent properties.Visualisation experiments revealed that the tensile stress gradient of the blood coagulum with increasing thickness under a thermal field prompted it to separate from the Al_(2)O_(3)@BSS surface,resulting in anti-adhesion.Furthermore,it was observed for the first time that Al_(2)O_(3) films could transiently excite discharge along a dielectric surface(DADS)to ablate tissues while suppressing Joule heat,thereby minimising thermal damage.A combination of ex vivo tissue and living mouse experiments demonstrated that the Al_(2)O_(3)@BSS electrodes exhibited optimal comprehensive performance in terms of anti-adhesion,damage minimisation,and drag reduction.In addition,the Al_(2)O_(3)@BSS electrodes possessed remarkable antibacterial efficacy against E.coli and S.aureus.The proposed strategy can meet the extreme application requirements of surgical electrodes to improve operation quality and offer valuable insights for future studies.展开更多
Amorphous Ga_(2)O_(3)(a-Ga_(2)O_(3))thin films were prepared on flexible polyimide,rigid quartz glass,and Si substrates via radio frequency magnetron sputtering at room temperature.The effect of oxygen/Ar flow rate ra...Amorphous Ga_(2)O_(3)(a-Ga_(2)O_(3))thin films were prepared on flexible polyimide,rigid quartz glass,and Si substrates via radio frequency magnetron sputtering at room temperature.The effect of oxygen/Ar flow rate ratio on the structure,optical property,surface morphology,and chemical bonding properties of the a-Ga_(2)O_(3) films was investigated.Results show that the average optical transmittance of the a-Ga_(2)O_(3) films is over 80%within the wavelength range of 300-2000 nm.The extracted optical band gap of the a-Ga_(2)O_(3) films is increased from 4.97 eV to 5.13 eV with the increase in O_(2)/Ar flow rate ratio from 0 to 0.25,due to the decrease in concentration of oxygen vacancy defects in the film.Furthermore,the optical refractive index and surface roughness of the a-Ga_(2)O_(3) films are optimized when the O_(2)/Ar flow rate ratio reaches 0.25.X-ray photoelectron spectroscopy analysis also shows that the proportion of oxygen vacancies(VO)and Ga-O chemical bonds in the O 1s peak is gradually decreased with the increase in O_(2)/Ar flow rate ratio from 0 to 0.25,proving that increasing the O_(2)/Ar flow rate ratio during film growth can reduce the concentration of oxygen vacancy defects in a-Ga_(2)O_(3) films.In this case,a-Ga_(2)O_(3) with optimal properties can be obtained.This work provides a research basis for high-performance flexible and rigid deep ultraviolet solar-blind detection devices based on a-Ga_(2)O_(3) films.展开更多
The emergence of cesium lead halide perovskite materials stable at air opened new prospects for the optoelectronic industry.In this work we present an approach to fabricating a flexible green perovskite light-emitting...The emergence of cesium lead halide perovskite materials stable at air opened new prospects for the optoelectronic industry.In this work we present an approach to fabricating a flexible green perovskite light-emitting electrochemical cell(PeLEC)with a CsPbBr_(3)perovskite active layer using a highly-ordered silicon nanowire(Si NW)array as a distributed electrode integrated within a thin polydimethylsiloxane film(PDMS).Numerical simulations reveal that Si NWs-based distributed electrode aids the improvement of carrier injection into the perovskite layer with an increased thickness and,therefore,the enhancement of light-emitting performance.The X-ray diffraction study shows that the perovskite layer synthesized on the PDMS membrane with Si NWs has a similar crystal structure to the ones synthesized on planar Si wafers.We perform a comparative analysis of the light-emitting devices’properties fabricated on rigid silicon substrates and flexible Si NW-based membranes released from substrates.Due to possible potential barriers in a flexible PeLEC between the bottom electrode(made of a network of single-walled carbon nanotube film)and Si NWs,the electroluminescence performance and Ⅰ-V properties of flexible devices deteriorated compared to rigid devices.The developed PeLECs pave the way for further development of inorganic flexible uniformly light-emitting devices with improved properties.展开更多
The p-n junction is the foundation building structure for manufacturing various electronic and optoelec-tronic devices.Ultrawide bandgap semiconductors are expected to overcome the limited power capability of Si-based...The p-n junction is the foundation building structure for manufacturing various electronic and optoelec-tronic devices.Ultrawide bandgap semiconductors are expected to overcome the limited power capability of Si-based electronic device,however,it is very difficult to achieve efficient bipolar doping due to the asymmetric doping effect,thereby impeding the development of p-n homojunction and related bipolar devices,especially for the Ga_(2)O_(3)-based materials and devices.Here,we demonstrate a unique one-step integrated growth of p-type N-doped(201)β-Ga_(2)O_(3)/n-type Si-doped(¯201)β-Ga_(2)O_(3)films by phase tran-sition and in-situ pre-doping of dopants,and fabrication of fullβ-Ga_(2)O_(3)linearly-graded p-n homojunc-tion diode from them.The fullβ-Ga_(2)O_(3)p-n homojunction diode possesses a large built-in potential of 4.52 eV,a high operation electric field>2.90 MV/cm in the reverse-bias regime,good longtime-stable rectifying behaviors with a rectification ratio of 104,and a high-speed switching and good surge robust-ness with a weak minority-carrier charge storage.Our work opens the way to the fabrication of Ga_(2)O_(3)-based p-n homojunction,lays the foundation for fullβ-Ga_(2)O_(3)-based bipolar devices,and paves the way for the novel fabrication of p-n homojunction for wide-bandgap oxides.展开更多
Optimizing the orientation of β-Ga_(2)O_(3) has emerged as an effective strategy to design high-performance β-Ga_(2)O_(3) device,but the orientation growth mechanism and approach have not been revealed yet.Herein,by...Optimizing the orientation of β-Ga_(2)O_(3) has emerged as an effective strategy to design high-performance β-Ga_(2)O_(3) device,but the orientation growth mechanism and approach have not been revealed yet.Herein,by employing AlN buffer layer,the highly preferred orientation of β-Ga_(2)O_(3)(100)film rather than(-201)film is realized on 4H-SiC substrate at low sputtering power and temperature.Because β-Ga_(2)O_(3)(100)film exhibits a slower growth speed than(-201)film,the former possesses the higher dangling bond density and the lower nucleation energy,and a large conversion barrier exists between these two ori-entations.Moreover,the AlN buffer layer can suppress the surface oxidation of the 4H-SiC substrate and eliminate the strain of β-Ga_(2)O_(3)(100)film,which further reduces the nucleation energy and en-larges the conversion barrier.Meanwhile,the AlN buffer layer can increase the oxygen vacancy formation energy and decrease the oxygen vacancy concentration of β-Ga_(2)O_(3)(100)film.Consequently,the solar-blind photodetector based on the oriented film exhibits the outstanding detectivity of 1.22×10^(12) Jones and photo-to-dark current ratio of 1.11×10^(5),which are the highest among the reported β-Ga_(2)O_(3) solar-blind photodetector on the SiC substrate.Our results offer in-depth insights into the preferred orientation growth mechanism,and provide an effective way to design high-quality β-Ga_(2)O_(3)(100)orientation film and high-performance solar-blind photodetector.展开更多
Mg_(3)Bi_(2)-based flms are promising near-room-temperature thermoelectric materials for the development of fexible thermoelectric devices.However,the high hole concentration caused by the abundance of intrinsic Mg va...Mg_(3)Bi_(2)-based flms are promising near-room-temperature thermoelectric materials for the development of fexible thermoelectric devices.However,the high hole concentration caused by the abundance of intrinsic Mg vacancies easily leads to deterioration of electrical properties,especially for p-type Mg_(3)Bi_(2) flm.And the optimization of thermal conductivity of the Mg_(3)Bi_(2)-based flms is barely investigated.In this work,we demonstrate the improved thermoelectric performances of p-type Mg_(3)Bi_(2) through Ag doping by magnetron sputtering.This doping successfully reduces the hole concentration and broadens the band gap of Mg_(3)Bi_(2),thus resulting in a peak power factor of 442μW m^(−1) K^(−2) at 525 K.At the same time,Ag doping-induced fuctuations in mass and microscopic strain efectively enhanced the phonon scattering to reduce the lattice thermal conductivity.Consequently,a maximum thermoelectric fgure of merit of 0.22 is achieved at 525 K.Its near-roomtemperature thermoelectric performances demonstrate superior performance compared to many Mg_(3)Bi_(2)-based flms.To further evaluate its potential for thermoelectric power generation,we fabricated a thermoelectric device using Ag-doped Mg_(3)Bi_(2) flms,which achieved a power density of 864μW cm^(⁻2) at 35 K temperature diference.This study presents an efective strategy for the advancement of Mg_(3)Bi_(2)-based flms for application in micro-thermoelectric devices.展开更多
Hexagonal GaN nanorods are synthesized on quartz substrates through ammoniating Ga 2O 3 thin films deposited by radio frequency magnetron sputtering.X ray diffraction (XRD),scanning electron microscopy (SEM),high ...Hexagonal GaN nanorods are synthesized on quartz substrates through ammoniating Ga 2O 3 thin films deposited by radio frequency magnetron sputtering.X ray diffraction (XRD),scanning electron microscopy (SEM),high resolution transmission electron microscopy (HRTEM),and photoluminescence (PL) are used to analyze the synthesized GaN nanorods.Among the products,one dimensional GaN nanostructures owning protuberances on the surface are detected,which show interesting herringbone morphology.The analysis reveals that the herringbone GaN nanorods are polycrystalline composed of overlapping parallelepiped GaN nanocrystals arranged along the major axis.The large blue shift of yellow PL luminescence of the nanorods is observed at room temperature.展开更多
Erbium-doped BaTiO3 films on LaNiO3/Si substrates were fabricated by sol-gel method. The crystalline structure, morphologies and upconversion （UC） luminescence properties of films were respectively investigated by X...Erbium-doped BaTiO3 films on LaNiO3/Si substrates were fabricated by sol-gel method. The crystalline structure, morphologies and upconversion （UC） luminescence properties of films were respectively investigated by X-ray diffraction （XRD）, atomic force microcopy （AFM） and photoluminescence （PL）. The results indicate that both of the microstructure and luminescence are found to be dependent on Er^3＋ substituting sites. The samples with A-site substitution have smaller lattice constants, larger grains and smoother surface than those with B-site substitution. The photoluminescence spectra show that both of the samples have two stronger green emission bands centered at 528 and 548 nm and a weak red emission band centered at 673 nm, which correspond to the relaxation of Er^3＋ from ^2H11/2, ^4S3/2, and ^4F9/2 levels to the ground level ^4I15/2, respectively. Compared with B-site doped films, A-site doped films have a stronger integrated intensity of green emissions and a weaker relative intensity of red emissions. The differences could be explained by the crystalline quality and cross relaxation （CR） process.展开更多
Copper nitride （Cu3N） films were prepared by reactive radio frequency magnetron sputtering at various nitrogen partial pressures, and the films were annealed at different temperatures. The crystal structure of the f...Copper nitride （Cu3N） films were prepared by reactive radio frequency magnetron sputtering at various nitrogen partial pressures, and the films were annealed at different temperatures. The crystal structure of the films was identified by X-ray diffraction technique. The Cu3N films have a cubic anti-ReO3 structure, and lattice constant is 0.3855 nm. With increasing nitrogen partial pressure, the Cu3N films are strongly textured with the crystal direction [100]. The atomic force microscope images show that the films presence a smooth and compact morphology with nanocrystallites of about 70 nm in size. The films were further characterized by UV-visible spectrometer, and the optical band gap of the films was calculated from the Tauc equation. The typical value of optical band gap of the films is about 1.75 eV, and it increases with increasing nitrogen partial pressure. The thermal property of the films was measured by thermogravimetry, and the decomposition temperature of the films was about 530 K.展开更多
Y2O3：Er^3＋ films were prepared by a simple sol-gel process. The structural properties of Y2O3：Er^3＋ films were characterized with X-ray diffraction, Fourier transform infrared spectroscopy and field emission scann...Y2O3：Er^3＋ films were prepared by a simple sol-gel process. The structural properties of Y2O3：Er^3＋ films were characterized with X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The results indicated that the Y2O3：Er^3＋ films might have high upconversion efficiency because of their low vibrational energy. Under 785 and 980 nm laser excitation, the samples showed green （^2H11/2→^4I15/2, ^4S3/2→^4I15/2） and red （^4F9/2→^4I15/2） upconversion emissions. The upconversion mechanisms were studied in detail through laser power dependence. Excited state absorption and energy transfer process were discussed as possible upconversion mechanisms. The cross relaxation process in Er^3＋ was also investigated.展开更多
Transparent conductive oxide ZnSnO3 films were prepared by radio-frequency magnetron sputtering from powder targets and were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron ...Transparent conductive oxide ZnSnO3 films were prepared by radio-frequency magnetron sputtering from powder targets and were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, atomic force microscopy, surface profile, UV-Vis spectroscopy, and Hall effect. The structures of the films were either amorphous or nanocrystalline depending on sputtering parameters including deposition time, target power, chamber pressure, and the target-substrate separation. The average transmittance of the ZnSnO3 films within the visible wavelength was approximately 80% and the resistivity of the ZnSnO3 films was in the range of 10^-3-10^-4 Ω cm. The structural, optical, and electrical properties of the ZnSnO3 films could be adjusted and regulated by optimizing the sputtering process, allowing materials with specific properties to be designed.展开更多
Two-inch Ga_2O_3 films with（ˉ201）-orientation are grown on c-sapphire at 850–1050°C by hydride vapor phase epitaxy. High-resolution x-ray diffraction shows that pure β-Ga_2O_3 with a smooth surface has a hig...Two-inch Ga_2O_3 films with（ˉ201）-orientation are grown on c-sapphire at 850–1050°C by hydride vapor phase epitaxy. High-resolution x-ray diffraction shows that pure β-Ga_2O_3 with a smooth surface has a higher crystal quality, and the Raman spectra reveal a very small residual strain in β-Ga_2O_3 grown by hydride vapor phase epitaxy compared with bulk single crystal. The optical transmittance is higher than 80% in the visible and near-UV regions, and the optical bandgap energy is calculated to be 4.9 e V.展开更多
Bil_xTbxFe03 thin films were prepared on Sn02 （fluorine doped tin oxide） substrates by a sol-gel method. The structural and electrical properties of the BiFe03 thin films were characterized and tested. The results i...Bil_xTbxFe03 thin films were prepared on Sn02 （fluorine doped tin oxide） substrates by a sol-gel method. The structural and electrical properties of the BiFe03 thin films were characterized and tested. The results indicated that the diffraction peak of the Tb-doped BiFe03 films was shifted towards right as the doping amounts were increased. The structure was transformed from the rhombohedral to tetragonal/orthorhombic phase. The Bio.sgTbo.11Fe03 thin film showed the well-developed P-E loops, which enhanced remnant polarization （Pr = 88.05 μC/cm2） at room temperature. The dielectric constant and dielectric loss of Bio.sgTbo.llFe03 thin film at 100 kHz were 185 and 0.018, respectively. Furthermore, the Bio.seTbo.llFe03 thin film showed a relatively low leakage current density of 2.07×10-5 A/cm2 at an applied electric field of 150 kV/cm. The X- ray photoelectron spectroscopy （XPS） spectra indicated that the presence of Fe2＋ ions in the Bio.egTbo.11Fe03 thin film was less than that in the pure BiFe03.展开更多
Atomic layer deposition （ALD） technique is used in the preparation of organic/inorganic layers, which requires uniform surfaces with their thickness down to several nanometers. For film with such thickness, the grow...Atomic layer deposition （ALD） technique is used in the preparation of organic/inorganic layers, which requires uniform surfaces with their thickness down to several nanometers. For film with such thickness, the growth mode defined as the arrangement of clusters on the surface during the growth is of significance. In this work, Al2O3 thin film was deposited on various interfacial species of pre-treated polyethylene terephthalate （PET, 12 μm） by plasma assisted atomic layer deposition （PA-ALD）, where trimethyl aluminium was used as the Al precursor and O2 as the oxygen source. The interracial species, -NH3, -OH, and -COOH as well as SiCHO （derived from monomer of HMDSO plasma）, were grafted previously by plasma and chemical treatments. The growth mode of PA-ALD Al2O3 was then investigated in detail by combining results from in-situ diagnosis of spectroscopic ellipsometry （SE） and ex-situ characterization of as-deposited layers from the morphologies scanned by atomic force microscopy （AFM）. In addition, the oxygen transmission rates （OTR） of the original and treated plastic films were measured. The possible reasons for the dependence of the OTR values on the surface species were explored.展开更多
A comparative study of the crystalline structure, magnetic properties, and transport properties of LSMO films grown on （100）-, （110）-, and （111） LaAlO3（LAO） substrates was carried out. Using atomic force micro...A comparative study of the crystalline structure, magnetic properties, and transport properties of LSMO films grown on （100）-, （110）-, and （111） LaAlO3（LAO） substrates was carried out. Using atomic force microscopy, round, rectangle, and dot surface morphologies were observed in （ 100）-, （ 110）-, and （ 111 ）-oriented LSMO films, respectively. Electrical and magnetic characterizations were performed on LSMO films of different orientation to provide evidence for the effect of strain on the magnetotransport properties. The （ 111 ）-oriented LSMO film has higher saturation magnetization and lower resistance compared with the （100）- and （110）-oriented LSMO films, which results from the smaller elastic deformation due to the larger elastic modulus along the 〈 111 〉 crystallographic direction.展开更多
3C-SiC films have been deposited on Si （111） substrates by the low-pressure vertical chemical vapor deposition （LPVCVD） with gas mixtures of SiH4, Calls and H2. The growth mechanism of SiC films can be obtained th...3C-SiC films have been deposited on Si （111） substrates by the low-pressure vertical chemical vapor deposition （LPVCVD） with gas mixtures of SiH4, Calls and H2. The growth mechanism of SiC films can be obtained through the observations using field emission scanning electron microscope （FESEM）. It is found that the growth process varies from surface control to diffusion control when the deposition temperature increases from 1270 to 1350℃. The X-ray diffraction （XRD） patterns show that the SiC films have good crystallinity and strong preferred orientation.The results of the high resolution transmission electron microscopy （HRTEM） image and the transmission electron diffraction （TED） pattern indicate a peculiar superlattice structure of the film. The values of the binding energy in the high resolution X-ray photoelectron spectra （XPS） further confirm the formation of SiC.展开更多
Bi0.85La0.15FeO3 thin film was prepared on ATO glass substrates by sol-gel technique. The effect of La doping on phase structure, film surface quality, ion valence, and ferroelectric/magnetic properties of Bio.85La0.1...Bi0.85La0.15FeO3 thin film was prepared on ATO glass substrates by sol-gel technique. The effect of La doping on phase structure, film surface quality, ion valence, and ferroelectric/magnetic properties of Bio.85La0.15FeO3 film were investigated. La doping suppressed the formation of impurity phases and the transition of Fe3＋ to Fe2＋ ions at room temperature. Compared with the un-doped BiFeO3, La-doping also increased the average grain size and the film density, which resulted in the decrease of film leakage current density. The remanent polarization and saturation magnetization were enhanced significantly by La doping. The remanent polariza- tion of Bi0.85La0.15FeO3 films gradually decreased while saturation magnetization increased with the decrease of measuring tempera- ture within a range from 50 to 300 K.展开更多
基金supported by the National Key Research and Development Programs-Intergovernmental International Cooperation in Science and Technology Innovation Project(Grant No.2022YFE0118400)the Natural Science Foundation of Hunan Province(2023JJ50132)+1 种基金Shenzhen Science and Technology Innovation Committee(Grants Nos.JCYJ20220818100211025,and KCXST20221021111616039)Shenzhen Science and Technology Program(No.20231128110928003)。
文摘The introduction of two-dimensional(2D)perovskite layers on top of three-dimensional(3D)perovskite films enhances the performance and stability of perovskite solar cells(PSCs).However,the electronic effect of the spacer cation and the quality of the 2D capping layer are critical factors in achieving the required results.In this study,we compared two fluorinated salts:4-(trifluoromethyl)benzamidine hydrochloride(4TF-BA·HCl)and 4-fluorobenzamidine hydrochloride(4F-BA·HCl)to engineer the 3D/2D perovskite films.Surprisingly,4F-BA formed a high-performance 3D/2D heterojunction,while4TF-BA produced an amorphous layer on the perovskite films.Our findings indicate that the balanced intramolecular charge polarization,which leads to effective hydrogen bonding,is more favorable in 4F-BA than in 4TF-BA,promoting the formation of a crystalline 2D perovskite.Nevertheless,4TF-BA managed to improve efficiency to 24%,surpassing the control device,primarily due to the natural passivation capabilities of benzamidine.Interestingly,the devices based on 4F-BA demonstrated an efficiency exceeding 25%with greater longevity under various storage conditions compared to 4TF-BA-based and the control devices.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52275425,52405473,and 52405472)the Natural Science Foundation of Guangdong Province(Grant No.2024A1515010993)。
文摘Surgical electrodes are frequently associated with disadvantages such as high surface adhesion and severe thermal damage to adjacent normal tissues,which threaten operation quality and patient safety.In this study,by mimicking the micromorphology and bio-anti-adhesion of shark skin,we proposed a strategy that utilized nanoscale aluminium oxide(Al_(2)O_(3))films deposited on bioinspired shark skin(BSS)microstructures to design a composite surface(Al_(2)O_(3)@BSS)and integrated it into both flat sides of the surgical electrodes.Micro/nano-manufacturing of the Al_(2)O_(3)@BSS surface was sequentially accomplished using nanosecond laser texturing,atomic layer deposition,and low-temperature annealing,endowing it with excellent blood-repellent properties.Visualisation experiments revealed that the tensile stress gradient of the blood coagulum with increasing thickness under a thermal field prompted it to separate from the Al_(2)O_(3)@BSS surface,resulting in anti-adhesion.Furthermore,it was observed for the first time that Al_(2)O_(3) films could transiently excite discharge along a dielectric surface(DADS)to ablate tissues while suppressing Joule heat,thereby minimising thermal damage.A combination of ex vivo tissue and living mouse experiments demonstrated that the Al_(2)O_(3)@BSS electrodes exhibited optimal comprehensive performance in terms of anti-adhesion,damage minimisation,and drag reduction.In addition,the Al_(2)O_(3)@BSS electrodes possessed remarkable antibacterial efficacy against E.coli and S.aureus.The proposed strategy can meet the extreme application requirements of surgical electrodes to improve operation quality and offer valuable insights for future studies.
基金Research Project of Shenzhen Science and Technology Innovation Committee(JCYJ20180306170801080)。
文摘Amorphous Ga_(2)O_(3)(a-Ga_(2)O_(3))thin films were prepared on flexible polyimide,rigid quartz glass,and Si substrates via radio frequency magnetron sputtering at room temperature.The effect of oxygen/Ar flow rate ratio on the structure,optical property,surface morphology,and chemical bonding properties of the a-Ga_(2)O_(3) films was investigated.Results show that the average optical transmittance of the a-Ga_(2)O_(3) films is over 80%within the wavelength range of 300-2000 nm.The extracted optical band gap of the a-Ga_(2)O_(3) films is increased from 4.97 eV to 5.13 eV with the increase in O_(2)/Ar flow rate ratio from 0 to 0.25,due to the decrease in concentration of oxygen vacancy defects in the film.Furthermore,the optical refractive index and surface roughness of the a-Ga_(2)O_(3) films are optimized when the O_(2)/Ar flow rate ratio reaches 0.25.X-ray photoelectron spectroscopy analysis also shows that the proportion of oxygen vacancies(VO)and Ga-O chemical bonds in the O 1s peak is gradually decreased with the increase in O_(2)/Ar flow rate ratio from 0 to 0.25,proving that increasing the O_(2)/Ar flow rate ratio during film growth can reduce the concentration of oxygen vacancy defects in a-Ga_(2)O_(3) films.In this case,a-Ga_(2)O_(3) with optimal properties can be obtained.This work provides a research basis for high-performance flexible and rigid deep ultraviolet solar-blind detection devices based on a-Ga_(2)O_(3) films.
基金the Russian Science Foundation Project No.22-79-10286,https://rscf.ru/project/22-7910286/(synthesis of perovskites, PeLEC fabrication)the Russian Science Foundation Project No.23-79-01151 for NW/PDMS membrane fabrication and PeLEC characterization+1 种基金the Ministry of Science and Higher Education of the Russian Federation (Project. FZSR-2020-0007 within the framework of state task no. 075-03-2020-097/1) for the support of SWCNT synthesisthe Ministry of Science and Higher Education of the Russian Federation (Project FSRM-2022-0007) for NW fabrication
文摘The emergence of cesium lead halide perovskite materials stable at air opened new prospects for the optoelectronic industry.In this work we present an approach to fabricating a flexible green perovskite light-emitting electrochemical cell(PeLEC)with a CsPbBr_(3)perovskite active layer using a highly-ordered silicon nanowire(Si NW)array as a distributed electrode integrated within a thin polydimethylsiloxane film(PDMS).Numerical simulations reveal that Si NWs-based distributed electrode aids the improvement of carrier injection into the perovskite layer with an increased thickness and,therefore,the enhancement of light-emitting performance.The X-ray diffraction study shows that the perovskite layer synthesized on the PDMS membrane with Si NWs has a similar crystal structure to the ones synthesized on planar Si wafers.We perform a comparative analysis of the light-emitting devices’properties fabricated on rigid silicon substrates and flexible Si NW-based membranes released from substrates.Due to possible potential barriers in a flexible PeLEC between the bottom electrode(made of a network of single-walled carbon nanotube film)and Si NWs,the electroluminescence performance and Ⅰ-V properties of flexible devices deteriorated compared to rigid devices.The developed PeLECs pave the way for further development of inorganic flexible uniformly light-emitting devices with improved properties.
基金supported by the National Key R&D Program of China(Grant Nos.2022YFB3605500 and 2022YFB3605503).
文摘The p-n junction is the foundation building structure for manufacturing various electronic and optoelec-tronic devices.Ultrawide bandgap semiconductors are expected to overcome the limited power capability of Si-based electronic device,however,it is very difficult to achieve efficient bipolar doping due to the asymmetric doping effect,thereby impeding the development of p-n homojunction and related bipolar devices,especially for the Ga_(2)O_(3)-based materials and devices.Here,we demonstrate a unique one-step integrated growth of p-type N-doped(201)β-Ga_(2)O_(3)/n-type Si-doped(¯201)β-Ga_(2)O_(3)films by phase tran-sition and in-situ pre-doping of dopants,and fabrication of fullβ-Ga_(2)O_(3)linearly-graded p-n homojunc-tion diode from them.The fullβ-Ga_(2)O_(3)p-n homojunction diode possesses a large built-in potential of 4.52 eV,a high operation electric field>2.90 MV/cm in the reverse-bias regime,good longtime-stable rectifying behaviors with a rectification ratio of 104,and a high-speed switching and good surge robust-ness with a weak minority-carrier charge storage.Our work opens the way to the fabrication of Ga_(2)O_(3)-based p-n homojunction,lays the foundation for fullβ-Ga_(2)O_(3)-based bipolar devices,and paves the way for the novel fabrication of p-n homojunction for wide-bandgap oxides.
基金supported by the National Key Research and Development Program of China(No.2021YFA0715600)the National Natural Science Foundation of China(Nos.62274125,52192611)+2 种基金the Guangdong Basic and Applied Basic Research Fund(No.2023A1515030084)the Key Research and Development Program of Shaanxi Province(Grant No.2024GX-YBXM-410)the fund of the State Key Laboratory of Solidification Processing in NWPU(No.SKLSP202220).
文摘Optimizing the orientation of β-Ga_(2)O_(3) has emerged as an effective strategy to design high-performance β-Ga_(2)O_(3) device,but the orientation growth mechanism and approach have not been revealed yet.Herein,by employing AlN buffer layer,the highly preferred orientation of β-Ga_(2)O_(3)(100)film rather than(-201)film is realized on 4H-SiC substrate at low sputtering power and temperature.Because β-Ga_(2)O_(3)(100)film exhibits a slower growth speed than(-201)film,the former possesses the higher dangling bond density and the lower nucleation energy,and a large conversion barrier exists between these two ori-entations.Moreover,the AlN buffer layer can suppress the surface oxidation of the 4H-SiC substrate and eliminate the strain of β-Ga_(2)O_(3)(100)film,which further reduces the nucleation energy and en-larges the conversion barrier.Meanwhile,the AlN buffer layer can increase the oxygen vacancy formation energy and decrease the oxygen vacancy concentration of β-Ga_(2)O_(3)(100)film.Consequently,the solar-blind photodetector based on the oriented film exhibits the outstanding detectivity of 1.22×10^(12) Jones and photo-to-dark current ratio of 1.11×10^(5),which are the highest among the reported β-Ga_(2)O_(3) solar-blind photodetector on the SiC substrate.Our results offer in-depth insights into the preferred orientation growth mechanism,and provide an effective way to design high-quality β-Ga_(2)O_(3)(100)orientation film and high-performance solar-blind photodetector.
基金supported by the National Natural Science Foundation of China(Nos.52073290 and 51927803)the Science Fund for Distinguished Young Scholars of Liaoning Province(No.2023JH6/100500004)the Shenyang Science and Technology Plan Project(No.23-407-3-23).
文摘Mg_(3)Bi_(2)-based flms are promising near-room-temperature thermoelectric materials for the development of fexible thermoelectric devices.However,the high hole concentration caused by the abundance of intrinsic Mg vacancies easily leads to deterioration of electrical properties,especially for p-type Mg_(3)Bi_(2) flm.And the optimization of thermal conductivity of the Mg_(3)Bi_(2)-based flms is barely investigated.In this work,we demonstrate the improved thermoelectric performances of p-type Mg_(3)Bi_(2) through Ag doping by magnetron sputtering.This doping successfully reduces the hole concentration and broadens the band gap of Mg_(3)Bi_(2),thus resulting in a peak power factor of 442μW m^(−1) K^(−2) at 525 K.At the same time,Ag doping-induced fuctuations in mass and microscopic strain efectively enhanced the phonon scattering to reduce the lattice thermal conductivity.Consequently,a maximum thermoelectric fgure of merit of 0.22 is achieved at 525 K.Its near-roomtemperature thermoelectric performances demonstrate superior performance compared to many Mg_(3)Bi_(2)-based flms.To further evaluate its potential for thermoelectric power generation,we fabricated a thermoelectric device using Ag-doped Mg_(3)Bi_(2) flms,which achieved a power density of 864μW cm^(⁻2) at 35 K temperature diference.This study presents an efective strategy for the advancement of Mg_(3)Bi_(2)-based flms for application in micro-thermoelectric devices.
文摘Hexagonal GaN nanorods are synthesized on quartz substrates through ammoniating Ga 2O 3 thin films deposited by radio frequency magnetron sputtering.X ray diffraction (XRD),scanning electron microscopy (SEM),high resolution transmission electron microscopy (HRTEM),and photoluminescence (PL) are used to analyze the synthesized GaN nanorods.Among the products,one dimensional GaN nanostructures owning protuberances on the surface are detected,which show interesting herringbone morphology.The analysis reveals that the herringbone GaN nanorods are polycrystalline composed of overlapping parallelepiped GaN nanocrystals arranged along the major axis.The large blue shift of yellow PL luminescence of the nanorods is observed at room temperature.
基金Project (2009AA035002) supported by the High-tech Research and Development Program of China
文摘Erbium-doped BaTiO3 films on LaNiO3/Si substrates were fabricated by sol-gel method. The crystalline structure, morphologies and upconversion （UC） luminescence properties of films were respectively investigated by X-ray diffraction （XRD）, atomic force microcopy （AFM） and photoluminescence （PL）. The results indicate that both of the microstructure and luminescence are found to be dependent on Er^3＋ substituting sites. The samples with A-site substitution have smaller lattice constants, larger grains and smoother surface than those with B-site substitution. The photoluminescence spectra show that both of the samples have two stronger green emission bands centered at 528 and 548 nm and a weak red emission band centered at 673 nm, which correspond to the relaxation of Er^3＋ from ^2H11/2, ^4S3/2, and ^4F9/2 levels to the ground level ^4I15/2, respectively. Compared with B-site doped films, A-site doped films have a stronger integrated intensity of green emissions and a weaker relative intensity of red emissions. The differences could be explained by the crystalline quality and cross relaxation （CR） process.
基金supported by the National Natural Science Foundation of China (Garnt No. 11064003)the Guangxi Natural Science Foundation of China(2010GXNSFA013122)
文摘Copper nitride （Cu3N） films were prepared by reactive radio frequency magnetron sputtering at various nitrogen partial pressures, and the films were annealed at different temperatures. The crystal structure of the films was identified by X-ray diffraction technique. The Cu3N films have a cubic anti-ReO3 structure, and lattice constant is 0.3855 nm. With increasing nitrogen partial pressure, the Cu3N films are strongly textured with the crystal direction [100]. The atomic force microscope images show that the films presence a smooth and compact morphology with nanocrystallites of about 70 nm in size. The films were further characterized by UV-visible spectrometer, and the optical band gap of the films was calculated from the Tauc equation. The typical value of optical band gap of the films is about 1.75 eV, and it increases with increasing nitrogen partial pressure. The thermal property of the films was measured by thermogravimetry, and the decomposition temperature of the films was about 530 K.
基金supported by the grants from the Nature Science Foundation of Zhejiang Province (Y406309)Research Program from Science and Technology Bureau of Jinhua City (2008-1-151)
文摘Y2O3：Er^3＋ films were prepared by a simple sol-gel process. The structural properties of Y2O3：Er^3＋ films were characterized with X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The results indicated that the Y2O3：Er^3＋ films might have high upconversion efficiency because of their low vibrational energy. Under 785 and 980 nm laser excitation, the samples showed green （^2H11/2→^4I15/2, ^4S3/2→^4I15/2） and red （^4F9/2→^4I15/2） upconversion emissions. The upconversion mechanisms were studied in detail through laser power dependence. Excited state absorption and energy transfer process were discussed as possible upconversion mechanisms. The cross relaxation process in Er^3＋ was also investigated.
基金financially supported by the National Natural Science Foundation of China (Nos. 51372109 and 51502126)the Foundation of Educational Department of Liaoning (No. L2015260)the Open Subject of Key Laboratory Liaoning Province (No. USTLKFSY201501)
文摘Transparent conductive oxide ZnSnO3 films were prepared by radio-frequency magnetron sputtering from powder targets and were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, atomic force microscopy, surface profile, UV-Vis spectroscopy, and Hall effect. The structures of the films were either amorphous or nanocrystalline depending on sputtering parameters including deposition time, target power, chamber pressure, and the target-substrate separation. The average transmittance of the ZnSnO3 films within the visible wavelength was approximately 80% and the resistivity of the ZnSnO3 films was in the range of 10^-3-10^-4 Ω cm. The structural, optical, and electrical properties of the ZnSnO3 films could be adjusted and regulated by optimizing the sputtering process, allowing materials with specific properties to be designed.
基金Supported by the National Key Research and Development Program of China under Grant No 2017YFB0404201the Solid State Lighting and Energy-Saving Electronics Collaborative Innovation Center,PAPDthe State Grid Shandong Electric Power Company
文摘Two-inch Ga_2O_3 films with（ˉ201）-orientation are grown on c-sapphire at 850–1050°C by hydride vapor phase epitaxy. High-resolution x-ray diffraction shows that pure β-Ga_2O_3 with a smooth surface has a higher crystal quality, and the Raman spectra reveal a very small residual strain in β-Ga_2O_3 grown by hydride vapor phase epitaxy compared with bulk single crystal. The optical transmittance is higher than 80% in the visible and near-UV regions, and the optical bandgap energy is calculated to be 4.9 e V.
基金supported by the Project of the National Natural Science Foundation of China(Grant No.51172135)the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.51002092)+1 种基金Research and Special Projects of the Education Department of Shaanxi Province(Grant No.12JK0445)the Graduate Innovation Fund of Shaanxi University of Science and Technology(SUST-A04)
文摘Bil_xTbxFe03 thin films were prepared on Sn02 （fluorine doped tin oxide） substrates by a sol-gel method. The structural and electrical properties of the BiFe03 thin films were characterized and tested. The results indicated that the diffraction peak of the Tb-doped BiFe03 films was shifted towards right as the doping amounts were increased. The structure was transformed from the rhombohedral to tetragonal/orthorhombic phase. The Bio.sgTbo.11Fe03 thin film showed the well-developed P-E loops, which enhanced remnant polarization （Pr = 88.05 μC/cm2） at room temperature. The dielectric constant and dielectric loss of Bio.sgTbo.llFe03 thin film at 100 kHz were 185 and 0.018, respectively. Furthermore, the Bio.seTbo.llFe03 thin film showed a relatively low leakage current density of 2.07×10-5 A/cm2 at an applied electric field of 150 kV/cm. The X- ray photoelectron spectroscopy （XPS） spectra indicated that the presence of Fe2＋ ions in the Bio.egTbo.11Fe03 thin film was less than that in the pure BiFe03.
基金supported by National Natural Science Foundation of China (No.11175024)Beijing Natural Science Foundation (No.1112012),2011BAD24B01+1 种基金Scientific Research Common Program of Beijing Municipal Commission of Education(KM201110015008,KM201010015005)Funding Project for Academic Human Resources Development in Institutions of Higher Learning Under theJurisdiction of Beijing Municipality (PHR20110516)
文摘Atomic layer deposition （ALD） technique is used in the preparation of organic/inorganic layers, which requires uniform surfaces with their thickness down to several nanometers. For film with such thickness, the growth mode defined as the arrangement of clusters on the surface during the growth is of significance. In this work, Al2O3 thin film was deposited on various interfacial species of pre-treated polyethylene terephthalate （PET, 12 μm） by plasma assisted atomic layer deposition （PA-ALD）, where trimethyl aluminium was used as the Al precursor and O2 as the oxygen source. The interracial species, -NH3, -OH, and -COOH as well as SiCHO （derived from monomer of HMDSO plasma）, were grafted previously by plasma and chemical treatments. The growth mode of PA-ALD Al2O3 was then investigated in detail by combining results from in-situ diagnosis of spectroscopic ellipsometry （SE） and ex-situ characterization of as-deposited layers from the morphologies scanned by atomic force microscopy （AFM）. In addition, the oxygen transmission rates （OTR） of the original and treated plastic films were measured. The possible reasons for the dependence of the OTR values on the surface species were explored.
基金Project supported bythe Key Basic Research Project of MOST(2002CCC01300) the Natural Science Foundation of Beijing(2021003) the Science &Technology Development Project of Beijing Education Committee and Beijing Specific Projectto Foster Elitist (20041D0501513)
文摘A comparative study of the crystalline structure, magnetic properties, and transport properties of LSMO films grown on （100）-, （110）-, and （111） LaAlO3（LAO） substrates was carried out. Using atomic force microscopy, round, rectangle, and dot surface morphologies were observed in （ 100）-, （ 110）-, and （ 111 ）-oriented LSMO films, respectively. Electrical and magnetic characterizations were performed on LSMO films of different orientation to provide evidence for the effect of strain on the magnetotransport properties. The （ 111 ）-oriented LSMO film has higher saturation magnetization and lower resistance compared with the （100）- and （110）-oriented LSMO films, which results from the smaller elastic deformation due to the larger elastic modulus along the 〈 111 〉 crystallographic direction.
基金Financial support from the National Natural Science Foundation of China under the grant No.50132040 is grate-fully acknowledged.
文摘3C-SiC films have been deposited on Si （111） substrates by the low-pressure vertical chemical vapor deposition （LPVCVD） with gas mixtures of SiH4, Calls and H2. The growth mechanism of SiC films can be obtained through the observations using field emission scanning electron microscope （FESEM）. It is found that the growth process varies from surface control to diffusion control when the deposition temperature increases from 1270 to 1350℃. The X-ray diffraction （XRD） patterns show that the SiC films have good crystallinity and strong preferred orientation.The results of the high resolution transmission electron microscopy （HRTEM） image and the transmission electron diffraction （TED） pattern indicate a peculiar superlattice structure of the film. The values of the binding energy in the high resolution X-ray photoelectron spectra （XPS） further confirm the formation of SiC.
基金Project supported by National Natural Science Foundation of China(51072163,51001085)
文摘Bi0.85La0.15FeO3 thin film was prepared on ATO glass substrates by sol-gel technique. The effect of La doping on phase structure, film surface quality, ion valence, and ferroelectric/magnetic properties of Bio.85La0.15FeO3 film were investigated. La doping suppressed the formation of impurity phases and the transition of Fe3＋ to Fe2＋ ions at room temperature. Compared with the un-doped BiFeO3, La-doping also increased the average grain size and the film density, which resulted in the decrease of film leakage current density. The remanent polarization and saturation magnetization were enhanced significantly by La doping. The remanent polariza- tion of Bi0.85La0.15FeO3 films gradually decreased while saturation magnetization increased with the decrease of measuring tempera- ture within a range from 50 to 300 K.
