Polycrystalline CuInS2 （CIS） films were prepared by sulphurization of Cu-In films. The surface morphology and phase composition of the as-grown film, the KCN-etched film, and the annealed KCN-etched film were invest...Polycrystalline CuInS2 （CIS） films were prepared by sulphurization of Cu-In films. The surface morphology and phase composition of the as-grown film, the KCN-etched film, and the annealed KCN-etched film were investigated. During the sulphurization, the secondary CuxS phase segregated on the surface of the as-grown films. To improve the crystalline quality of CuInS2 films, a series of post-grown treatments, such as KCN-etching and vacuum annealing KCN-etched films, were performed on the as-grown films. Both as-grown and post-treated films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. The results indicated that a CuxS secondary phase segregated on the surface of the as-grown film, which could be removed effectively by KCN etching. After the vacuum annealing treatment, the KCN-etched film had a sphalerite structure with （112） preferred orientation. Meanwhile, the crystalline quality of the CIS film was significantly improved, which provided a novel method to improve the performance of thin film solar cells.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
Tetravalent tin(Sn^(4+))-based inorganic perovskite semiconductors like Cs_(2)SnI_(6)are expected to replace lead-based perovskite counterparts due to advantages such as structural stability and environmental friendli...Tetravalent tin(Sn^(4+))-based inorganic perovskite semiconductors like Cs_(2)SnI_(6)are expected to replace lead-based perovskite counterparts due to advantages such as structural stability and environmental friendliness.In this paper,we reported the dopant compensation effect in the component-dependent self-doped(111)-oriented Cs_(2)SnI_(6)thin films grown with pulsed laser deposition(PLD)at room temperature.The films were grown on(100)-SrTiO_(3)(STO)substrates at room temperature by PLD.Hall results of the Cs_(2)SnI_(6)films with different components realizing by controlling the ratio of SnI_(4)/CsI in the targets demonstrate a clear change of conductivity type from N-type to P-type,while the carrier concentration decreases from 1018 to 1013 and accordingly the film resistivity increases significantly from 3.8 to 2506Ωcm.The defect-relatedopticalfingerprints of Cs_(2)SnI_(6)films werealsoinvestigated withtemperature-dependent photoluminescence spectroscopy.At low temperatures of 10 K,the Cs_(2)SnI_(6)films exhibit donor-bound(D^(0)X)and donor-acceptor pair(DAP)emission,respectively,due to the self-doping effect.These re-sults indicate that controlling the composition of the PLD target is a powerful way to tune the electrical properties of Cs_(2)SnI_(6)films for possible applications in solar cells or X-ray detectors.展开更多
Innovative use of HfO_(2)-based high-dielectric-permittivity materials could enable their integration into few-nanometre-scale devices for storing substantial quantities of electrical charges,which have received wides...Innovative use of HfO_(2)-based high-dielectric-permittivity materials could enable their integration into few-nanometre-scale devices for storing substantial quantities of electrical charges,which have received widespread applications in high-storage-density dynamic random access memory and energy-efficient complementary metal-oxide-semiconductor devices.During bipolar high electric-field cycling in numbers close to dielectric breakdown,the dielectric permittivity suddenly increases by 30 times after oxygen-vacancy ordering and ferroelectric-to-nonferroelectric phase transition of near-edge plasma-treated Hf_(0.5)Zr_(0.5)O_(2) thin-film capacitors.Here we report a much higher dielectric permittivity of 1466 during downscaling of the capacitor into the diameter of 3.85μm when the ferroelectricity suddenly disappears without high-field cycling.The stored charge density is as high as 183μC cm^(−2) at an operating voltage/time of 1.2 V/50 ns at cycle numbers of more than 10^(12) without inducing dielectric breakdown.The study of synchrotron X-ray micro-diffraction patterns show missing of a mixed tetragonal phase.The image of electron energy loss spectroscopy shows the preferred oxygen-vacancy accumulation at the regions near top/bottom electrodes as well as grain boundaries.The ultrahigh dielectric-permittivity material enables high-density integration of extremely scaled logic and memory devices in the future.展开更多
CuInSe2 （CIS） films with good crystalline quality were synthesized by electrodeposition followed by annealing in Se vapor at 530 ℃. The morphology, composition, crystal structure, optical and electrical properties ...CuInSe2 （CIS） films with good crystalline quality were synthesized by electrodeposition followed by annealing in Se vapor at 530 ℃. The morphology, composition, crystal structure, optical and electrical properties of the CIS films were investigated by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Raman spectroscopy, UV-VISNIR spectroscopy, and admittance spectroscopy. The results revealed that the annealed CIS films had chalcopyrite structure and consisted of relatively large grains in the range of 500-1000 nm and single grain of films extend usually through the whole film thickness. The band gap of CIS films was 0.98 eV and carrier concentration was in the order of 1016 cm-3 after etching the Cu-Se compounds on the film surface. Solar cells with the structure of AZO/i-ZnO/CdS/CIS/Mo/glass were fabricated. Current density vs. voltage test under standard reported condition showed the solar cells with an area of 0.2 cm2 had a conversion efficiency of 0.96%. The underlying physics was also discussed.展开更多
Transparent conductive oxide （TCO） thin film is a kind of functional material which has potential applications in solar cells and atomic oxygen （AO） resisting systems in spacecrafts. Of TCO, ZnO：Al （ZAO） and In...Transparent conductive oxide （TCO） thin film is a kind of functional material which has potential applications in solar cells and atomic oxygen （AO） resisting systems in spacecrafts. Of TCO, ZnO：Al （ZAO） and In2O3：Sn （ITO） thin films have been widely used and investigated. In this study, ZAO and ITO thin films were irradiated by AO with different amounts of fluence. The as-deposited samples and irradiated ones were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and Hall-effect measurement to investigate the dependence of the structure, morphology and electrical properties of ZAO or ITO on the amount of fluence of AO irradiation. It is noticed that AO has erosion effects on the surface of ZAO without evident influences upon its structure and conductive properties. Moreover, as the amount of AO fluence rises, the carrier concentration of ITO decreases causing the resistivity to increase by at most 21.7%.展开更多
Tungsten-doped indium oxide (IWO) thin films were deposited on glass substrate by DC reactive magnetron sputtering. The effects of sputtering power and growth temperature on the structure, surface morphology, optical ...Tungsten-doped indium oxide (IWO) thin films were deposited on glass substrate by DC reactive magnetron sputtering. The effects of sputtering power and growth temperature on the structure, surface morphology, optical and electrical properties of IWO thin films were investigated. The thickness and surface morphology of the films are both closely dependent on the sputtering power and the substrate temperature. The transparency of the films decreases with the increase of the sputtering power but is not seriously influenced by substrate temperature. All the IWO thin film samples have high transmittance in near-infrared spectral range. With either the sputtering power or the growth temperature increases, the resistivity of the film decreases at the beginning and increases after the optimum parameters. The as-deposited IWO films with minimum resistivity of 6.4 10 4 cm were obtained at a growth temperature of225 C and sputteringpower of 40 W, with carrier mobility of 33.0 cm 2 V 1 s 1 and carrier concentration of 2.8 10 20 cm 3 and the average transmittance of about 81% in near-infrared region and about 87% in visible region.展开更多
With rapid progressive application of TiO2 thin films, magnetron sputtering becomes a very interesting method to prepare such multi-functional thin films. This paper focuses on influences of various deposition process...With rapid progressive application of TiO2 thin films, magnetron sputtering becomes a very interesting method to prepare such multi-functional thin films. This paper focuses on influences of various deposition processes and deposition rate on the structures and properties of TiO2 thin films. Anatase, rutile or amorphous TiO2 films with various crystalline structures and different photocatalytic, optical and electrical properties can be produced by varying sputtering gases, substrate temperature, annealing process, deposition rate and the characteristics of magnetron sputtering. This may in turn affect the functions of TiO2 films in many applications. Furthermore, TiO2-based composites films can overcome many limitations and improve the properties of TiO2 films.展开更多
Cu2ZnSnS4 (CZTS) thin films were successfully prepared by sulfurization of ion bean sputtered precursors on soda-lime glass substrate. The single phase of stannite-type structure CZTS films were obtained as revealed i...Cu2ZnSnS4 (CZTS) thin films were successfully prepared by sulfurization of ion bean sputtered precursors on soda-lime glass substrate. The single phase of stannite-type structure CZTS films were obtained as revealed in EDS and XRD analysis when the ratios of the constituents of CZTS thin films are close to stoichiometric by optimizing the conditions of precursor preparation and sulfurization. A low sheet resistivity as about 0.156 Ω·cm and a high absorption coefficient as 1×104 cm-1 were achieved in this method by Hall effect measurements and UV-VIS spectrophotometer. The optical band-gap energy of the CZTS sample is about 1.51 eV, which is very close to the optimum value for a solar-cell absorber.展开更多
CuIn（S,Se）2 thin films were prepared by thermal crystallization of co-sputtered Cu-In alloy precursors in S/Se atmosphere. In-depth compositional uniformity is an important prereq- uisite for obtaining device-qualit...CuIn（S,Se）2 thin films were prepared by thermal crystallization of co-sputtered Cu-In alloy precursors in S/Se atmosphere. In-depth compositional uniformity is an important prereq- uisite for obtaining device-quality CuIn（S,Se）2 absorber thin films. In order to figure out the influence of heat treatments on in-depth composition uniformity of CuIn（S,Se）2 thin films, two kinds of reaction temperature profiles were investigated. One process is ＂one step profile＂, referring to formation of CuIn（S,Se）2 thin films just at elevated temperature （e.g. 500 ℃）. The other is ＂two step profile＂, which allows for slow diffusion of S and Se elements into the alloy precursors at a low temperature before the formation and re-crystallization of CuIn（S,Se）2 thin films at higher temperature （e.g. first 250 ℃ then 500 ℃）. X-ray diffrac- tion studies reveal that there is a discrepancy in the shape of （112） peak. Samples annealed with ＂one step profile＂ have splits on （112） peaks, while samples annealed with ＂two step profile＂ have relatively symmetrical （112） peaks. Grazing incident X-ray diffraction and en- ergy dispersive spectrum measurements of samples successively etched in bromine methanol show that CuIn（S,Se）2 thin films have better in-depth composition uniformity after ＂two step profile＂ annealing. The reaction mechanism during the two thermal processing was also investigated by X-ray diffraction and Raman spectra.展开更多
Polyaniline （PANI）, polyaniline/titanium dioxide （PANI/TiO2）, polyaniline/tin oxide （PANI/SnO2） and polyaniline/indium oxide （PANI/In203） thin films were developed by using an in-situ self-assembly method at ...Polyaniline （PANI）, polyaniline/titanium dioxide （PANI/TiO2）, polyaniline/tin oxide （PANI/SnO2） and polyaniline/indium oxide （PANI/In203） thin films were developed by using an in-situ self-assembly method at -10℃. Chemical structure, optical property and morphology of all the thin films were characterized by X-ray diffraction （XRD）, Fourier transform infrared （FTIR） spectroscopy, UV-Vis absorption spectroscopy, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. NH3 gas-sensing properties of PANI and PANI nanocomposite thin films were examined at ambient temperature. The results showed that all the sensors composed of PANI nanocomposite thin films had faster response/recovery rate with better reproducibility, selectivity and long-term stability to NH3 than PANI,thiS film sensor, and PANI/TiO2 nanocomposite thin film sensor showed optimum NH3 gas-sensing characteristics. The effect of humidity on the responses of all the sensors was also investigated.展开更多
Nano-structured SiO2 thin films were prepared on the surface of carbon steel for the first time by LPD. The compositions of the films were analyzed by XPS, and the surface morphology of the thin films were observed b...Nano-structured SiO2 thin films were prepared on the surface of carbon steel for the first time by LPD. The compositions of the films were analyzed by XPS, and the surface morphology of the thin films were observed by AFM. The thin films were constituted by compact particles of SiO2, and there was no Fe in the films. In the process of film forming, the SiO2 colloid particles were deposited or absorbed directly onto the surface of carbon steel substrates that were activated by acid solution containing inhibitor, and corrosion of the substrates was avoided. The nano-structured SiO2 thin films that were prepared had excellent protective efficiency to the carbon steel.展开更多
Two kinds of TiO_2 nanometer thin films were prepared on stainless steel bythe reverse micellar and sol-gel methods, respectively. The calcined TiO_ 2 thin films werecharacterized by X-ray diffraction (XRD), atomic fo...Two kinds of TiO_2 nanometer thin films were prepared on stainless steel bythe reverse micellar and sol-gel methods, respectively. The calcined TiO_ 2 thin films werecharacterized by X-ray diffraction (XRD), atomic force microscopy (AFM), BET surface area and X-rayphotoelectron spectroscopy (XPS). Photocatalytic activity was evaluated by photocatalyticdecoloration of methyl orange aqueous solution. The results showed that the TiO_2 thin filmsprepared by reverse micellar method (designated as RM-TiO_2 films) showed higher photocatalyticactivity than those by sol-gel method (designated as SG-TiO_2 films). This is attributed to the factthat the former is composed of smaller monodispersed spherical particles with a size of about 15 nmand possesses higher surface areas.展开更多
Ag TiO 2 thin films were prepared on glasses.The morphology and structure of Ag TiO 2 films were investigated by XRD, SEM and FT IR.The photocatalytic and hydrophilic properties of Ag TiO 2 thin films were also...Ag TiO 2 thin films were prepared on glasses.The morphology and structure of Ag TiO 2 films were investigated by XRD, SEM and FT IR.The photocatalytic and hydrophilic properties of Ag TiO 2 thin films were also evaluated by examining photocatalytic degradation dichlorophos under sunlight illumination and the change of contact angle respectively.The research results show that the Ag TiO 2 thin film is mainly composed of 20-100nm Ag and TiO 2 particles.The Ag TiO 2 thin films possess a super hydrophilic ability and higher photocatalytic activity than that of pure TiO 2 thin film.展开更多
The transparent anatase TiO 2 nanometer thin films were prepared by the sol-gel method on soda-lime glass.X-ray diffraction,thermal analysis and UV-visible spectrophotometer were used to analyze the formation of the ...The transparent anatase TiO 2 nanometer thin films were prepared by the sol-gel method on soda-lime glass.X-ray diffraction,thermal analysis and UV-visible spectrophotometer were used to analyze the formation of the phases.Only increasing the heat-treatment time,the average grain size has no obvious change.The mechanism of grain growth in TiO 2 thin film is probably as follows:the grain of coating will become grain core later;TiO 2 sol constantly deposited on the surface of TiO 2 grain and formed membrane with increasing of coating cycle times;TiO 2 grain in the film grow steadily.展开更多
Anatase TiO2 sol was synthesized under mild conditions （75℃ and ambient pressure） by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room te...Anatase TiO2 sol was synthesized under mild conditions （75℃ and ambient pressure） by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room temperature and in ambient atmosphere, crystalline TiO2 thin films were deposited on polymethylmethacrylate （PMMA）, SiO2-coated PMMA and SiO2-coated silicone rubber substrates from the as-prepared TiO2 sol by a dip-coating process. SiO2 layers prior to TiO2 thin films on polymer substrates could not only protect the substrates from the photocatalytic decomposition of the TiO2 thin films but also enhance the adhesion of the TiO2 thin films to the substrates. Field-emission type scanning electron microscope （FE-SEM） investigations revealed that the average particle sizes of the nanoparticles composing the TiO2 thin films were about 35-47 nm. The TiO2 thin films exhibited high photocatalytic activities in the degradation of reactive brilliant red dye X-3B in aqueous solution under aerated conditions. The preparation process of photocatalytic TiO2 thin films on the polymer substrates was quite simple and a low temperature route.展开更多
The chemical structures, optical properties and laser-induced damage thresholds of magnesium fluoride films annealed at different temperatures were investigated. The results showed that the stoichiometry of MgF2 film ...The chemical structures, optical properties and laser-induced damage thresholds of magnesium fluoride films annealed at different temperatures were investigated. The results showed that the stoichiometry of MgF2 film changed a little with the increase in annealing temperature. Analysis of the optical properties indicated that excellent antireflection behavior of the film in the range of 200-400 nm can be obtained by the samples coated with MgF2 film. The refractive index increased and the extinction coefficient decreased with increasing annealing temperature. Compared with the asdeposited films, the laser-induced damage threshold was improved after annealing process and decreased with the increase in annealing temperature, which was probably due to the denser film and more absorption centers under higher annealing temperature.展开更多
The present work describes the effect of deposition potentials on structural,morphological,optical,electrical and photoconductivity responses of cuprous oxide(Cu2O)thin films deposited on fluorine-doped tin oxide glas...The present work describes the effect of deposition potentials on structural,morphological,optical,electrical and photoconductivity responses of cuprous oxide(Cu2O)thin films deposited on fluorine-doped tin oxide glass substrate by employing electrodeposition technique.X-ray diffraction patterns reveal that the deposited films have a cubic structure grown along the preferential(111)growth orientation and crystallinity of the film deposited at.0.4 V is improved compared to the films deposited at.0.2,.0.3 and.0.5 V.Scanning electron microscopy displays that surface morphology of Cu2O film has a well-defined three-sided pyramid-shaped grains which are uniformly distributed over the surface of the substrates and are significantly changed as a function of deposition potential.Raman and photoluminescence spectra manifest that the film deposited at.0.4 V has a good crystal quality with higher acceptor concentration compared to other films.UV–visible analysis illustrates that the absorption of Cu2O thin film deposited at.0.4 V is notably higher compared to other films and the band gap of Cu2O thin films decreases from 2.1 to 2.04 eV with an increase in deposition potential from.0.2 to.0.5 V.The frequency–temperature dependence of impedance analysis shows that the film deposited at.0.4 V has a high conductivity.I– V measurements elucidate that the film deposited at.0.4 V exhibits a good photoconductivity response compared to films deposited in other deposition potentials.展开更多
Pb-doped TiO2 photocatalytic thin films were prepared on a soda-lime glass substrate via sol-gel method using TiO2 sol solution containing lead and characterized by X-ray photoelectron spectroscopy (XPS). The results ...Pb-doped TiO2 photocatalytic thin films were prepared on a soda-lime glass substrate via sol-gel method using TiO2 sol solution containing lead and characterized by X-ray photoelectron spectroscopy (XPS). The results showed that besides oxides of Ti(IV) there is a certain amount of oxides of To(?) and Ti(?) and Pb exists in the forms of PbTiO3 and PbO. The photocatalytic activity of the Pb-doped TiO2 films was evaluated by the photocatalytic decolorization of aqueous methyl orange and photocatalytic mechanism mas also analyzed.展开更多
基金the National High-Tech Research and Development Program of China (No. 2006AA03Z2370)
文摘Polycrystalline CuInS2 （CIS） films were prepared by sulphurization of Cu-In films. The surface morphology and phase composition of the as-grown film, the KCN-etched film, and the annealed KCN-etched film were investigated. During the sulphurization, the secondary CuxS phase segregated on the surface of the as-grown films. To improve the crystalline quality of CuInS2 films, a series of post-grown treatments, such as KCN-etching and vacuum annealing KCN-etched films, were performed on the as-grown films. Both as-grown and post-treated films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. The results indicated that a CuxS secondary phase segregated on the surface of the as-grown film, which could be removed effectively by KCN etching. After the vacuum annealing treatment, the KCN-etched film had a sphalerite structure with （112） preferred orientation. Meanwhile, the crystalline quality of the CIS film was significantly improved, which provided a novel method to improve the performance of thin film solar cells.
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financially supported by the National Key Re-search and Development Program of China(No.2022YFC3700801)the Key R&D Program of Shandong Province,China(No.2024SFGC0102),the Jinan Bureau of Education(No.JNSX2023015)the Jinan Bureau of Science and Technology(No.202333042).
文摘Tetravalent tin(Sn^(4+))-based inorganic perovskite semiconductors like Cs_(2)SnI_(6)are expected to replace lead-based perovskite counterparts due to advantages such as structural stability and environmental friendliness.In this paper,we reported the dopant compensation effect in the component-dependent self-doped(111)-oriented Cs_(2)SnI_(6)thin films grown with pulsed laser deposition(PLD)at room temperature.The films were grown on(100)-SrTiO_(3)(STO)substrates at room temperature by PLD.Hall results of the Cs_(2)SnI_(6)films with different components realizing by controlling the ratio of SnI_(4)/CsI in the targets demonstrate a clear change of conductivity type from N-type to P-type,while the carrier concentration decreases from 1018 to 1013 and accordingly the film resistivity increases significantly from 3.8 to 2506Ωcm.The defect-relatedopticalfingerprints of Cs_(2)SnI_(6)films werealsoinvestigated withtemperature-dependent photoluminescence spectroscopy.At low temperatures of 10 K,the Cs_(2)SnI_(6)films exhibit donor-bound(D^(0)X)and donor-acceptor pair(DAP)emission,respectively,due to the self-doping effect.These re-sults indicate that controlling the composition of the PLD target is a powerful way to tune the electrical properties of Cs_(2)SnI_(6)films for possible applications in solar cells or X-ray detectors.
基金supported by the National Key Basic Research Program of China (2022YFA1402904)Basic Research Project of Shanghai Science and Technology Innovation Action (grant number 24CL2900900)the National Natural Science Foundation of China (grant number 61904034)
文摘Innovative use of HfO_(2)-based high-dielectric-permittivity materials could enable their integration into few-nanometre-scale devices for storing substantial quantities of electrical charges,which have received widespread applications in high-storage-density dynamic random access memory and energy-efficient complementary metal-oxide-semiconductor devices.During bipolar high electric-field cycling in numbers close to dielectric breakdown,the dielectric permittivity suddenly increases by 30 times after oxygen-vacancy ordering and ferroelectric-to-nonferroelectric phase transition of near-edge plasma-treated Hf_(0.5)Zr_(0.5)O_(2) thin-film capacitors.Here we report a much higher dielectric permittivity of 1466 during downscaling of the capacitor into the diameter of 3.85μm when the ferroelectricity suddenly disappears without high-field cycling.The stored charge density is as high as 183μC cm^(−2) at an operating voltage/time of 1.2 V/50 ns at cycle numbers of more than 10^(12) without inducing dielectric breakdown.The study of synchrotron X-ray micro-diffraction patterns show missing of a mixed tetragonal phase.The image of electron energy loss spectroscopy shows the preferred oxygen-vacancy accumulation at the regions near top/bottom electrodes as well as grain boundaries.The ultrahigh dielectric-permittivity material enables high-density integration of extremely scaled logic and memory devices in the future.
文摘CuInSe2 （CIS） films with good crystalline quality were synthesized by electrodeposition followed by annealing in Se vapor at 530 ℃. The morphology, composition, crystal structure, optical and electrical properties of the CIS films were investigated by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Raman spectroscopy, UV-VISNIR spectroscopy, and admittance spectroscopy. The results revealed that the annealed CIS films had chalcopyrite structure and consisted of relatively large grains in the range of 500-1000 nm and single grain of films extend usually through the whole film thickness. The band gap of CIS films was 0.98 eV and carrier concentration was in the order of 1016 cm-3 after etching the Cu-Se compounds on the film surface. Solar cells with the structure of AZO/i-ZnO/CdS/CIS/Mo/glass were fabricated. Current density vs. voltage test under standard reported condition showed the solar cells with an area of 0.2 cm2 had a conversion efficiency of 0.96%. The underlying physics was also discussed.
基金National Natural Science Foundation of China (50471004)
文摘Transparent conductive oxide （TCO） thin film is a kind of functional material which has potential applications in solar cells and atomic oxygen （AO） resisting systems in spacecrafts. Of TCO, ZnO：Al （ZAO） and In2O3：Sn （ITO） thin films have been widely used and investigated. In this study, ZAO and ITO thin films were irradiated by AO with different amounts of fluence. The as-deposited samples and irradiated ones were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and Hall-effect measurement to investigate the dependence of the structure, morphology and electrical properties of ZAO or ITO on the amount of fluence of AO irradiation. It is noticed that AO has erosion effects on the surface of ZAO without evident influences upon its structure and conductive properties. Moreover, as the amount of AO fluence rises, the carrier concentration of ITO decreases causing the resistivity to increase by at most 21.7%.
基金supported by the National Natural Science Foundation of China (No. 50902006)the National High Technology Development 863 Program of China (No.2009AA03Z428)
文摘Tungsten-doped indium oxide (IWO) thin films were deposited on glass substrate by DC reactive magnetron sputtering. The effects of sputtering power and growth temperature on the structure, surface morphology, optical and electrical properties of IWO thin films were investigated. The thickness and surface morphology of the films are both closely dependent on the sputtering power and the substrate temperature. The transparency of the films decreases with the increase of the sputtering power but is not seriously influenced by substrate temperature. All the IWO thin film samples have high transmittance in near-infrared spectral range. With either the sputtering power or the growth temperature increases, the resistivity of the film decreases at the beginning and increases after the optimum parameters. The as-deposited IWO films with minimum resistivity of 6.4 10 4 cm were obtained at a growth temperature of225 C and sputteringpower of 40 W, with carrier mobility of 33.0 cm 2 V 1 s 1 and carrier concentration of 2.8 10 20 cm 3 and the average transmittance of about 81% in near-infrared region and about 87% in visible region.
文摘With rapid progressive application of TiO2 thin films, magnetron sputtering becomes a very interesting method to prepare such multi-functional thin films. This paper focuses on influences of various deposition processes and deposition rate on the structures and properties of TiO2 thin films. Anatase, rutile or amorphous TiO2 films with various crystalline structures and different photocatalytic, optical and electrical properties can be produced by varying sputtering gases, substrate temperature, annealing process, deposition rate and the characteristics of magnetron sputtering. This may in turn affect the functions of TiO2 films in many applications. Furthermore, TiO2-based composites films can overcome many limitations and improve the properties of TiO2 films.
基金This work was financially supported by the National Natural Science Foundation (No.10574106), the Science & Technology Plan of Guangdong Province (No.2003C105005) and the Scientific Research Foundation for the Returned Overseas Chinese Scholars of Chinese State Education Ministry (No.(2004)176).
文摘Cu2ZnSnS4 (CZTS) thin films were successfully prepared by sulfurization of ion bean sputtered precursors on soda-lime glass substrate. The single phase of stannite-type structure CZTS films were obtained as revealed in EDS and XRD analysis when the ratios of the constituents of CZTS thin films are close to stoichiometric by optimizing the conditions of precursor preparation and sulfurization. A low sheet resistivity as about 0.156 Ω·cm and a high absorption coefficient as 1×104 cm-1 were achieved in this method by Hall effect measurements and UV-VIS spectrophotometer. The optical band-gap energy of the CZTS sample is about 1.51 eV, which is very close to the optimum value for a solar-cell absorber.
文摘CuIn（S,Se）2 thin films were prepared by thermal crystallization of co-sputtered Cu-In alloy precursors in S/Se atmosphere. In-depth compositional uniformity is an important prereq- uisite for obtaining device-quality CuIn（S,Se）2 absorber thin films. In order to figure out the influence of heat treatments on in-depth composition uniformity of CuIn（S,Se）2 thin films, two kinds of reaction temperature profiles were investigated. One process is ＂one step profile＂, referring to formation of CuIn（S,Se）2 thin films just at elevated temperature （e.g. 500 ℃）. The other is ＂two step profile＂, which allows for slow diffusion of S and Se elements into the alloy precursors at a low temperature before the formation and re-crystallization of CuIn（S,Se）2 thin films at higher temperature （e.g. first 250 ℃ then 500 ℃）. X-ray diffrac- tion studies reveal that there is a discrepancy in the shape of （112） peak. Samples annealed with ＂one step profile＂ have splits on （112） peaks, while samples annealed with ＂two step profile＂ have relatively symmetrical （112） peaks. Grazing incident X-ray diffraction and en- ergy dispersive spectrum measurements of samples successively etched in bromine methanol show that CuIn（S,Se）2 thin films have better in-depth composition uniformity after ＂two step profile＂ annealing. The reaction mechanism during the two thermal processing was also investigated by X-ray diffraction and Raman spectra.
基金supported by the National Natural Science Foundation of China under grant Nos.60425101 and 60736005
文摘Polyaniline （PANI）, polyaniline/titanium dioxide （PANI/TiO2）, polyaniline/tin oxide （PANI/SnO2） and polyaniline/indium oxide （PANI/In203） thin films were developed by using an in-situ self-assembly method at -10℃. Chemical structure, optical property and morphology of all the thin films were characterized by X-ray diffraction （XRD）, Fourier transform infrared （FTIR） spectroscopy, UV-Vis absorption spectroscopy, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. NH3 gas-sensing properties of PANI and PANI nanocomposite thin films were examined at ambient temperature. The results showed that all the sensors composed of PANI nanocomposite thin films had faster response/recovery rate with better reproducibility, selectivity and long-term stability to NH3 than PANI,thiS film sensor, and PANI/TiO2 nanocomposite thin film sensor showed optimum NH3 gas-sensing characteristics. The effect of humidity on the responses of all the sensors was also investigated.
文摘Nano-structured SiO2 thin films were prepared on the surface of carbon steel for the first time by LPD. The compositions of the films were analyzed by XPS, and the surface morphology of the thin films were observed by AFM. The thin films were constituted by compact particles of SiO2, and there was no Fe in the films. In the process of film forming, the SiO2 colloid particles were deposited or absorbed directly onto the surface of carbon steel substrates that were activated by acid solution containing inhibitor, and corrosion of the substrates was avoided. The nano-structured SiO2 thin films that were prepared had excellent protective efficiency to the carbon steel.
基金This project is financially supported by the National Natural Science Foundation of China (No.s 50272049, 50072016) The Excellent Young Teachers Program of MOE, China (No. (2002)350)
文摘Two kinds of TiO_2 nanometer thin films were prepared on stainless steel bythe reverse micellar and sol-gel methods, respectively. The calcined TiO_ 2 thin films werecharacterized by X-ray diffraction (XRD), atomic force microscopy (AFM), BET surface area and X-rayphotoelectron spectroscopy (XPS). Photocatalytic activity was evaluated by photocatalyticdecoloration of methyl orange aqueous solution. The results showed that the TiO_2 thin filmsprepared by reverse micellar method (designated as RM-TiO_2 films) showed higher photocatalyticactivity than those by sol-gel method (designated as SG-TiO_2 films). This is attributed to the factthat the former is composed of smaller monodispersed spherical particles with a size of about 15 nmand possesses higher surface areas.
文摘Ag TiO 2 thin films were prepared on glasses.The morphology and structure of Ag TiO 2 films were investigated by XRD, SEM and FT IR.The photocatalytic and hydrophilic properties of Ag TiO 2 thin films were also evaluated by examining photocatalytic degradation dichlorophos under sunlight illumination and the change of contact angle respectively.The research results show that the Ag TiO 2 thin film is mainly composed of 20-100nm Ag and TiO 2 particles.The Ag TiO 2 thin films possess a super hydrophilic ability and higher photocatalytic activity than that of pure TiO 2 thin film.
文摘The transparent anatase TiO 2 nanometer thin films were prepared by the sol-gel method on soda-lime glass.X-ray diffraction,thermal analysis and UV-visible spectrophotometer were used to analyze the formation of the phases.Only increasing the heat-treatment time,the average grain size has no obvious change.The mechanism of grain growth in TiO 2 thin film is probably as follows:the grain of coating will become grain core later;TiO 2 sol constantly deposited on the surface of TiO 2 grain and formed membrane with increasing of coating cycle times;TiO 2 grain in the film grow steadily.
文摘Anatase TiO2 sol was synthesized under mild conditions （75℃ and ambient pressure） by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room temperature and in ambient atmosphere, crystalline TiO2 thin films were deposited on polymethylmethacrylate （PMMA）, SiO2-coated PMMA and SiO2-coated silicone rubber substrates from the as-prepared TiO2 sol by a dip-coating process. SiO2 layers prior to TiO2 thin films on polymer substrates could not only protect the substrates from the photocatalytic decomposition of the TiO2 thin films but also enhance the adhesion of the TiO2 thin films to the substrates. Field-emission type scanning electron microscope （FE-SEM） investigations revealed that the average particle sizes of the nanoparticles composing the TiO2 thin films were about 35-47 nm. The TiO2 thin films exhibited high photocatalytic activities in the degradation of reactive brilliant red dye X-3B in aqueous solution under aerated conditions. The preparation process of photocatalytic TiO2 thin films on the polymer substrates was quite simple and a low temperature route.
基金financially supported by the Research Fund of the State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,China(Grant No.155-QP-2016)the Fundamental Research Funds for the Central Universities(No.3102014JCQ01032)the 111 Project(No.B08040)
文摘The chemical structures, optical properties and laser-induced damage thresholds of magnesium fluoride films annealed at different temperatures were investigated. The results showed that the stoichiometry of MgF2 film changed a little with the increase in annealing temperature. Analysis of the optical properties indicated that excellent antireflection behavior of the film in the range of 200-400 nm can be obtained by the samples coated with MgF2 film. The refractive index increased and the extinction coefficient decreased with increasing annealing temperature. Compared with the asdeposited films, the laser-induced damage threshold was improved after annealing process and decreased with the increase in annealing temperature, which was probably due to the denser film and more absorption centers under higher annealing temperature.
基金the funding and support from the RUSA-Phase 2.0 grant sanctioned vide Letter. No. F. 24-51/2014-U, Policy (TNMulti-Gen), Dept. of Edn. Govt. of India. Dt. 09.10.2018.
文摘The present work describes the effect of deposition potentials on structural,morphological,optical,electrical and photoconductivity responses of cuprous oxide(Cu2O)thin films deposited on fluorine-doped tin oxide glass substrate by employing electrodeposition technique.X-ray diffraction patterns reveal that the deposited films have a cubic structure grown along the preferential(111)growth orientation and crystallinity of the film deposited at.0.4 V is improved compared to the films deposited at.0.2,.0.3 and.0.5 V.Scanning electron microscopy displays that surface morphology of Cu2O film has a well-defined three-sided pyramid-shaped grains which are uniformly distributed over the surface of the substrates and are significantly changed as a function of deposition potential.Raman and photoluminescence spectra manifest that the film deposited at.0.4 V has a good crystal quality with higher acceptor concentration compared to other films.UV–visible analysis illustrates that the absorption of Cu2O thin film deposited at.0.4 V is notably higher compared to other films and the band gap of Cu2O thin films decreases from 2.1 to 2.04 eV with an increase in deposition potential from.0.2 to.0.5 V.The frequency–temperature dependence of impedance analysis shows that the film deposited at.0.4 V has a high conductivity.I– V measurements elucidate that the film deposited at.0.4 V exhibits a good photoconductivity response compared to films deposited in other deposition potentials.
基金Natural Science Foundation of Hubei Province, China (No. 98J029)
文摘Pb-doped TiO2 photocatalytic thin films were prepared on a soda-lime glass substrate via sol-gel method using TiO2 sol solution containing lead and characterized by X-ray photoelectron spectroscopy (XPS). The results showed that besides oxides of Ti(IV) there is a certain amount of oxides of To(?) and Ti(?) and Pb exists in the forms of PbTiO3 and PbO. The photocatalytic activity of the Pb-doped TiO2 films was evaluated by the photocatalytic decolorization of aqueous methyl orange and photocatalytic mechanism mas also analyzed.
