We investigate the electronic and magnetic properties of the diluted magnetic semiconductors Zn1-xMnxS(001) thin films with different Mn doping concentrations using the total energy density functional theory. The en...We investigate the electronic and magnetic properties of the diluted magnetic semiconductors Zn1-xMnxS(001) thin films with different Mn doping concentrations using the total energy density functional theory. The energy stability and density of states of a single Mn atom and two Mn atoms at various doped configurations and different magnetic coupling state were calculated. Different doping configurations have different degrees of p-d hybridization, and because Mn atoms are located in different crystal-field environment, the 3d projected densities of states peak splitting of different Mn doping configurations are quite different. In the two Mn atoms doped, the calculated ground states of three kinds of stable configurations are anti-ferromagnetic state. We analyzed the 3d density of states diagram of three kinds of energy stability configurations with the two Mn atoms in different magnetic coupling state. When the two Mn atoms are ferromagnetic coupling, due to d-d electron interactions, density of states of anti-bonding state have significant broadening peaks. As the concentration of Mn atoms increases, there is a tendency for Mn atoms to form nearest neighbors and cluster around S. For such these configurations, the antiferromagnetic coupling between Mn atoms is energetically more favorable.展开更多
Cd_(1-x)Zn_(x)S thin films were deposited by chemical bath deposition(CBD)on the glass substrate to study the influence of cadmium sulfate concentration on the structural characteristics of the thin film.The SEM resul...Cd_(1-x)Zn_(x)S thin films were deposited by chemical bath deposition(CBD)on the glass substrate to study the influence of cadmium sulfate concentration on the structural characteristics of the thin film.The SEM results show that the thin film surfaces under the cadmium sulfate concentration of 0.005 M exhibit better compactness and uniformity.The distribution diagrams of thin film elements illustrate the film growth rate changes on the trend of the increase,decrease,and increase with the increase of cadmium sulfate concentration.XRD studies exhibit the crystal structure of the film is the hexagonal phase,and there are obvious diffraction peaks and better crystallinity when the concentration is 0.005 M.Spectrophotometer test results demonstrate that the relationship between zinc content x and optical band gap value E_(g) can be expressed by the equation E_(g)(x)=0.59x^(2)+0.69x+2.43.Increasing the zinc content can increase the optical band gap,and the absorbance of the thin film can be improved by decreasing the cadmium sulfate concentration,however,all of them have good transmittance.At a concentration of 0.005 M,the thin film has good absorbance in the 300-800 nm range,80%transmittance,and band gap value of 3.24 eV,which is suitable for use as a buffer layer for solar cells.展开更多
In this paper the dependence of structural properties of the quaternary CuIn1-xGaxSe2 films with tetragonal structure on the Ga content has been systematically investigated by Raman scattering and x-ray diffraction sp...In this paper the dependence of structural properties of the quaternary CuIn1-xGaxSe2 films with tetragonal structure on the Ga content has been systematically investigated by Raman scattering and x-ray diffraction spectra. The shift of the dominant A1 mode, unlike the lattice constants, does not follow the linear Vegard law with increasing Ga content x, whereas exhibits approximately polynomial change from 174 cm^-1 for CuInSe2 to 185 cm^-1 for CuGaSe2. Such behaviour should be indicative of presence of the asymmetric distribution of Ga and In on a microscopic scale in the films, due to Ga addition. The changes in the tetragonal distortion η lead to a significant variation in the anion displacement parameter U, which should be responsible for the evolution of bond parameters and resultant Raman bands with x.展开更多
Epitaxial (0001)-oriented Zn1-xCoxO (x= 0.01, 0.05 and 0.1) thin films were grown on c-sapphire substrates by pulsed laser deposition. The XRD analysis, optical transmittance and XPS measurements revealed that the...Epitaxial (0001)-oriented Zn1-xCoxO (x= 0.01, 0.05 and 0.1) thin films were grown on c-sapphire substrates by pulsed laser deposition. The XRD analysis, optical transmittance and XPS measurements revealed that the Co2+ substituted Zn2+ ions were incorporated into the lattice of ZnO in Zn1-xCoxO thin films. The electrical properties measurements revealed that the Co concentration had a non- monotonic influence on the electrical properties of the Zn1-xCoxO thin films due to the defects resulted from imperfections induced by Co substitution. The resistivity remarkably increased and the carrier concentration remarkably decreased in Zn1-x CoxO thin films after oxygen annealing at 600 ℃ under 15 Pa O2 pressure for 60 mins. Room-temperature ferromagnetic was observed and the ferromagnetic Co amount was smaller than the nominal Co concentration for Zn1-xCoxO samples before oxygen annealing. After oxygen annealing, the Zn1-x CoxO thin films exhibited paramagnetic behavior. It is suggested that the room-temperature ferromagnetic ofZn1-x CoxO thin films may attribute to defects or carriers induced mechanism.展开更多
TixAl1-xN films have been prepared by RF reactive magnetron sputtering. X-ray diffraction results showed that TixAl1-xN thin films in this study were hexagonal wurtzite structure with the Ti content up to 0.18. X-ray ...TixAl1-xN films have been prepared by RF reactive magnetron sputtering. X-ray diffraction results showed that TixAl1-xN thin films in this study were hexagonal wurtzite structure with the Ti content up to 0.18. X-ray photoelectron spectrocopy studies provided that the Nls core-electron spectrum of TixAl1-xN thin film brodend with increasing Ti content, and the difference of the chemical shifts for Ti2p3/2 line between TiN and TixAl1-xN th77pj in film was 0.7 eV.展开更多
A star-shaped compound of perfluoro-1-octanesulfonated fullerene was synthesized. The measurement of the friction for its spin-coating film by friction force microscopy (FFM) reveals that the films possess lower frict...A star-shaped compound of perfluoro-1-octanesulfonated fullerene was synthesized. The measurement of the friction for its spin-coating film by friction force microscopy (FFM) reveals that the films possess lower friction force compared to that of the star-shaped C-60-polystyrene films.展开更多
Stoichiometric Ba(MnxTi(1-x)O3) (BMT) thin films with various values of x were deposited on Si(111) substrates by the sol-gel technique. The influence of Mn content on the optical properties was studied by spe...Stoichiometric Ba(MnxTi(1-x)O3) (BMT) thin films with various values of x were deposited on Si(111) substrates by the sol-gel technique. The influence of Mn content on the optical properties was studied by spectroscopic ellipsometry (SE) in the UV–Vis–NIR region. By fitting the measured ellipsometric parameter (Ψ and Δ) with a four-phase model (air/BMT+voids/BMT/Si(111)), the key optical constants of the thin films have been obtained. It was found that the refractive index n and the extinction coefficient k increase with increasing Mn content due to the increase in the packing density. Furthermore, a strong dependence of the optical band gap Eg on Mn/Ti ratios in the deposited films was observed, and it was inferred that the energy level of conduction bands decreases with increasing Mn content.展开更多
Y_(1-x)Ho_xBa_2Cu_3O_(7-δ)(0<x<1) sinsle crystal thin films oriented with the caxis perpendicular to the sur-face were grown by DC magnetron sputtering technique. Target was pieced together with half of YBa_2Cu...Y_(1-x)Ho_xBa_2Cu_3O_(7-δ)(0<x<1) sinsle crystal thin films oriented with the caxis perpendicular to the sur-face were grown by DC magnetron sputtering technique. Target was pieced together with half of YBa_2Cu_3O_(7-δ)(YBCO) and half of HoBa_2Cu_3O_(7-δ)(HBCO) superconducting materials. As the distance between HBCO targetmaterial and substrate is varied , the Ho content in material is changed respectively. When the content of Ho is0. 7 (atom ratio) , the T_c>83K.展开更多
This paper reports that the transverse laser induced thermoelectric voltages (LITV) axe observed for the first time in the step flow growth (1- x)PD(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT, x = 0.20, 0.33, 0.50) thin fi...This paper reports that the transverse laser induced thermoelectric voltages (LITV) axe observed for the first time in the step flow growth (1- x)PD(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT, x = 0.20, 0.33, 0.50) thin films deposited on vicinal-cut strontium titanate single crystal substrates. Because lead magnesium niobate-lead titanate is a solid solution of lead magnesium niobate (PMN) and lead titanate (PT), there are two types of signals. One is wide with a time response of a microsecond, and the other superimposed with the wide signal is narrow with a time response of a nanosecond. The transverse LITV signals depend on the ratio of PMN to PT drastically. Under the irradiation of 28-ns pulsed KrF excimer laser with the 248-nm wavelength, the largest induced voltage is observed in the 0.50Pb(Mg1/3Nb2/3)O3-0.50 PbTiO3 films. Moreover, the effects of film thickness, substrates, and tilt angles of substrates are also investigated.展开更多
Tt-phase electron-doped superconductor Pr1-xLaCexCuO4-δ(PLCCO) thin films are successfully prepared on SrTiOs (100) substrates by using the dc magnetron sputtering method. It is found that the films each have a h...Tt-phase electron-doped superconductor Pr1-xLaCexCuO4-δ(PLCCO) thin films are successfully prepared on SrTiOs (100) substrates by using the dc magnetron sputtering method. It is found that the films each have a highly oriented structure along the c-axis. For optimally doped films with x ≈ 0.10, the superconducting transition temperature Tc is 25.5 K, which is similar to that of a single crystal. The quadratic temperature dependence of the resistivity is observed when T 〉 To, which can be attributed to the two-dimensional Fermi liquid behaviour. Besides, the optimal conditions for preparing the T1-phase PLCCO thin films are also discussed in detail.展开更多
MBE growth of ZnS_xSe_1-x thin films on ITO coated glass substrate s were carried o ut using ZnS and Se sources with the substrate temperature ranging from 270℃ to 330℃. The XRD θ/2θ spectra resulted from these...MBE growth of ZnS_xSe_1-x thin films on ITO coated glass substrate s were carried o ut using ZnS and Se sources with the substrate temperature ranging from 270℃ to 330℃. The XRD θ/2θ spectra resulted from these films indicated that the as-gro wn polycrystalline ZnS_xSe_1-x thin films had a preferred orientat ion along the (1 11) planes. The evaluated crystal sizes as deduced from the FWHM of the XRD laye r peaks showed strong growth temperature dependence, with the optimized temperat ure being about 290℃. Both AFM and TEM measurements of these thin films also in dicated a similar growth temperature dependence. High quality ZnS_xSe_1- x thin fil m grown at the optimized temperature had the smoothest surface with lowest RMS v alue of 1.2 nm and TEM cross-sectional micrograph showing a well defined column ar structure.展开更多
The CuxSi(1-x) thin films have been grown by pulsed laser deposition(PLD) with in situ annealing on Si(001) and Si(111),respectively.The transformation of phase was detected by X-ray diffraction(XRD).The res...The CuxSi(1-x) thin films have been grown by pulsed laser deposition(PLD) with in situ annealing on Si(001) and Si(111),respectively.The transformation of phase was detected by X-ray diffraction(XRD).The results showed that the as-deposited films were composed of Cu on both Si(001) and Si(111).The annealed thin films consisted of Cu +η "-Cu3Si on Si(001) while Cu +η'-Cu3Si on Si(111),respectively,at annealed temperature(Ta)= 300-600℃.With the further increasing of Ta,at Ta= 700℃,there was only one main phase,η"-Cu3Si on Si(001) while η'-Cu3Si on Si(111),respectively.The annealed thin films transformed from continuous dense structure to scattered-grain morphology with increasing Ta detected by field emission scanning electron microscope(FESEM).It was also showed that the grain size would enlarge with increasing annealing time(ta).展开更多
We present the results concerning photovoltaic materials CuIn1-xGaxSe2 thin films, which were obtained by close-spaced vapor transport “CSVT”. The influence of the iodine pressure on the growth of CuIn1-xGaxSe2 thin...We present the results concerning photovoltaic materials CuIn1-xGaxSe2 thin films, which were obtained by close-spaced vapor transport “CSVT”. The influence of the iodine pressure on the growth of CuIn1-xGaxSe2 thin films was studied. The thin films were characterized by Energy Dispersive Spectrometry (EDS), Scanning Electron Microscope (SEM), hot point probe method, X-Ray Diffraction (XRD), Photoluminescence, and Optical response (Photoconductivity). At high pressure, the deposition rate was very important. The films were relatively thick and homogeneous with large grains dimensions. These films are formed of crystals placed in a preferential orientation depending on the plan (112). At low pressure, the films were thin and inhomogeneous with relatively small grains. These films of crystals didn’t have preferential orientation.展开更多
Cadmium Cobalt Sulphide (CdxCo1-xS) thin film was deposited on microscopic glass substrate using chemical bath deposition technique at room temperature from aqueous solutions of Cadmium Chloride, Cobalt Chloride and T...Cadmium Cobalt Sulphide (CdxCo1-xS) thin film was deposited on microscopic glass substrate using chemical bath deposition technique at room temperature from aqueous solutions of Cadmium Chloride, Cobalt Chloride and Thiourea in which ammonium solution was used as complexing agents. The optical properties were characterized using the absorbance and transmission measurement from Unico UV-2102 PC spectrophotometer, at normal incidence of light in the wavelength range of 200 - 1000 nm. We report the deposition and optimization of the growth parameter with respect to time which showed that the band gap energy and the composition verified from the extended Vegard’s law are highly dependent on deposition time. The average transmittance of the film in VIS-NIR region ranges between 30% and 78% with absorbance range of 0.15 - 0.47 within the same wavelength range. The film was also observed to exhibit poor reflectance (11 x = 0.75;0.83 and 0.94), respectively. Other optical and dielectric properties of the films were also characterized. Based on the exhibited properties of the film, it can be concluded that it is a promising material for selective coatings for solar cells;effective coatings for poultry houses;use as antireflective coating materials, and for fabrication of optoelectronic devices.展开更多
文摘为延长‘红丰’梨采后贮藏保鲜期,提升果实贮藏品质,该试验采用不同厚度聚乙烯膜包装经0.4μL/L 1-甲基环丙烯(1-methylcyclopropene,1-MCP)保鲜剂处理后的‘红丰’梨果实,于冷藏期间测定果实相关指标,探索适宜聚乙烯膜包装厚度。结果表明,0.015 mm聚乙烯(polyethylene,PE)膜包装可有效维持果实硬度,延缓果皮转黄,延缓可溶性固形物和可滴定酸含量的增加,有效抑制总酚含量降低,降低果肉褐变指数,有效抑制丙二醛含量和相对电导率的增加,抑制多酚氧化酶活性,促进抗氧化关键酶活性。因此,0.015 mm PE膜包装可通过一定程度上维持细胞膜完整性,降低膜脂氧化程度,提高果实抗氧化能力从而延缓1-MCP处理果实衰老和果肉褐变。该试验为‘红丰’梨采后贮藏保鲜方式研究奠定了理论基础。
基金This work was supported by the National Natural Science Foundation of China (No.60776039 and No.60406005), the Natural Science Foundation of Beijing (No.3062016), and the School Foundation of Beijing Jiaotong University.
文摘We investigate the electronic and magnetic properties of the diluted magnetic semiconductors Zn1-xMnxS(001) thin films with different Mn doping concentrations using the total energy density functional theory. The energy stability and density of states of a single Mn atom and two Mn atoms at various doped configurations and different magnetic coupling state were calculated. Different doping configurations have different degrees of p-d hybridization, and because Mn atoms are located in different crystal-field environment, the 3d projected densities of states peak splitting of different Mn doping configurations are quite different. In the two Mn atoms doped, the calculated ground states of three kinds of stable configurations are anti-ferromagnetic state. We analyzed the 3d density of states diagram of three kinds of energy stability configurations with the two Mn atoms in different magnetic coupling state. When the two Mn atoms are ferromagnetic coupling, due to d-d electron interactions, density of states of anti-bonding state have significant broadening peaks. As the concentration of Mn atoms increases, there is a tendency for Mn atoms to form nearest neighbors and cluster around S. For such these configurations, the antiferromagnetic coupling between Mn atoms is energetically more favorable.
基金This work was supported by the Tianjin Municipal Education Commission,Horizontal subject(grant number 70304901).
文摘Cd_(1-x)Zn_(x)S thin films were deposited by chemical bath deposition(CBD)on the glass substrate to study the influence of cadmium sulfate concentration on the structural characteristics of the thin film.The SEM results show that the thin film surfaces under the cadmium sulfate concentration of 0.005 M exhibit better compactness and uniformity.The distribution diagrams of thin film elements illustrate the film growth rate changes on the trend of the increase,decrease,and increase with the increase of cadmium sulfate concentration.XRD studies exhibit the crystal structure of the film is the hexagonal phase,and there are obvious diffraction peaks and better crystallinity when the concentration is 0.005 M.Spectrophotometer test results demonstrate that the relationship between zinc content x and optical band gap value E_(g) can be expressed by the equation E_(g)(x)=0.59x^(2)+0.69x+2.43.Increasing the zinc content can increase the optical band gap,and the absorbance of the thin film can be improved by decreasing the cadmium sulfate concentration,however,all of them have good transmittance.At a concentration of 0.005 M,the thin film has good absorbance in the 300-800 nm range,80%transmittance,and band gap value of 3.24 eV,which is suitable for use as a buffer layer for solar cells.
基金Project supported by China Postdoctoral Science Foundation (Grant No 2005037539), and the National High-Tech Research and Development Programm of China (Grant No 2004AA513020). Acknowledgments 0ne of the authors (Xu Chuan-Ming) gratefully acknowledges Professor Xu Cun-Yi from the Structure Research Laboratory of Chinese Academy of Sciences for the sample measurements.
文摘In this paper the dependence of structural properties of the quaternary CuIn1-xGaxSe2 films with tetragonal structure on the Ga content has been systematically investigated by Raman scattering and x-ray diffraction spectra. The shift of the dominant A1 mode, unlike the lattice constants, does not follow the linear Vegard law with increasing Ga content x, whereas exhibits approximately polynomial change from 174 cm^-1 for CuInSe2 to 185 cm^-1 for CuGaSe2. Such behaviour should be indicative of presence of the asymmetric distribution of Ga and In on a microscopic scale in the films, due to Ga addition. The changes in the tetragonal distortion η lead to a significant variation in the anion displacement parameter U, which should be responsible for the evolution of bond parameters and resultant Raman bands with x.
基金Funded by New Century Excellent Talents in University(No.NCET-10-0662)International Science and Technology Cooperation Project of Hubei Province(No.2010BFA017)International Science&Technology Cooperation Program of China(No.2011DFA52650)
文摘Epitaxial (0001)-oriented Zn1-xCoxO (x= 0.01, 0.05 and 0.1) thin films were grown on c-sapphire substrates by pulsed laser deposition. The XRD analysis, optical transmittance and XPS measurements revealed that the Co2+ substituted Zn2+ ions were incorporated into the lattice of ZnO in Zn1-xCoxO thin films. The electrical properties measurements revealed that the Co concentration had a non- monotonic influence on the electrical properties of the Zn1-xCoxO thin films due to the defects resulted from imperfections induced by Co substitution. The resistivity remarkably increased and the carrier concentration remarkably decreased in Zn1-x CoxO thin films after oxygen annealing at 600 ℃ under 15 Pa O2 pressure for 60 mins. Room-temperature ferromagnetic was observed and the ferromagnetic Co amount was smaller than the nominal Co concentration for Zn1-xCoxO samples before oxygen annealing. After oxygen annealing, the Zn1-x CoxO thin films exhibited paramagnetic behavior. It is suggested that the room-temperature ferromagnetic ofZn1-x CoxO thin films may attribute to defects or carriers induced mechanism.
基金This work was supported by the National Natural Science Foundation of China under grant No.10474074the Hubei Natural Science Foundation under grant No.2001ABB060.
文摘TixAl1-xN films have been prepared by RF reactive magnetron sputtering. X-ray diffraction results showed that TixAl1-xN thin films in this study were hexagonal wurtzite structure with the Ti content up to 0.18. X-ray photoelectron spectrocopy studies provided that the Nls core-electron spectrum of TixAl1-xN thin film brodend with increasing Ti content, and the difference of the chemical shifts for Ti2p3/2 line between TiN and TixAl1-xN th77pj in film was 0.7 eV.
基金This project is financially supported by the National Natural Science Foundation of China (No. 50173001)
文摘A star-shaped compound of perfluoro-1-octanesulfonated fullerene was synthesized. The measurement of the friction for its spin-coating film by friction force microscopy (FFM) reveals that the films possess lower friction force compared to that of the star-shaped C-60-polystyrene films.
基金Project supported by the National Natural Science Foundation of China(Grant No.60976016)the Postdoctoral Science Foundation of China(Grant No.2012M511250)the Foundation Co-established by Henan Province and the Ministry of Henan University,China(Grant No.SBGJ090503)
文摘Stoichiometric Ba(MnxTi(1-x)O3) (BMT) thin films with various values of x were deposited on Si(111) substrates by the sol-gel technique. The influence of Mn content on the optical properties was studied by spectroscopic ellipsometry (SE) in the UV–Vis–NIR region. By fitting the measured ellipsometric parameter (Ψ and Δ) with a four-phase model (air/BMT+voids/BMT/Si(111)), the key optical constants of the thin films have been obtained. It was found that the refractive index n and the extinction coefficient k increase with increasing Mn content due to the increase in the packing density. Furthermore, a strong dependence of the optical band gap Eg on Mn/Ti ratios in the deposited films was observed, and it was inferred that the energy level of conduction bands decreases with increasing Mn content.
文摘Y_(1-x)Ho_xBa_2Cu_3O_(7-δ)(0<x<1) sinsle crystal thin films oriented with the caxis perpendicular to the sur-face were grown by DC magnetron sputtering technique. Target was pieced together with half of YBa_2Cu_3O_(7-δ)(YBCO) and half of HoBa_2Cu_3O_(7-δ)(HBCO) superconducting materials. As the distance between HBCO targetmaterial and substrate is varied , the Ho content in material is changed respectively. When the content of Ho is0. 7 (atom ratio) , the T_c>83K.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10274026)
文摘This paper reports that the transverse laser induced thermoelectric voltages (LITV) axe observed for the first time in the step flow growth (1- x)PD(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT, x = 0.20, 0.33, 0.50) thin films deposited on vicinal-cut strontium titanate single crystal substrates. Because lead magnesium niobate-lead titanate is a solid solution of lead magnesium niobate (PMN) and lead titanate (PT), there are two types of signals. One is wide with a time response of a microsecond, and the other superimposed with the wide signal is narrow with a time response of a nanosecond. The transverse LITV signals depend on the ratio of PMN to PT drastically. Under the irradiation of 28-ns pulsed KrF excimer laser with the 248-nm wavelength, the largest induced voltage is observed in the 0.50Pb(Mg1/3Nb2/3)O3-0.50 PbTiO3 films. Moreover, the effects of film thickness, substrates, and tilt angles of substrates are also investigated.
基金supported by the State Key Program for Basic Research of China(Grant No 2004CB619004-1)the National Natural Science Foundation of China(Grant No 10474121)
文摘Tt-phase electron-doped superconductor Pr1-xLaCexCuO4-δ(PLCCO) thin films are successfully prepared on SrTiOs (100) substrates by using the dc magnetron sputtering method. It is found that the films each have a highly oriented structure along the c-axis. For optimally doped films with x ≈ 0.10, the superconducting transition temperature Tc is 25.5 K, which is similar to that of a single crystal. The quadratic temperature dependence of the resistivity is observed when T 〉 To, which can be attributed to the two-dimensional Fermi liquid behaviour. Besides, the optimal conditions for preparing the T1-phase PLCCO thin films are also discussed in detail.
文摘MBE growth of ZnS_xSe_1-x thin films on ITO coated glass substrate s were carried o ut using ZnS and Se sources with the substrate temperature ranging from 270℃ to 330℃. The XRD θ/2θ spectra resulted from these films indicated that the as-gro wn polycrystalline ZnS_xSe_1-x thin films had a preferred orientat ion along the (1 11) planes. The evaluated crystal sizes as deduced from the FWHM of the XRD laye r peaks showed strong growth temperature dependence, with the optimized temperat ure being about 290℃. Both AFM and TEM measurements of these thin films also in dicated a similar growth temperature dependence. High quality ZnS_xSe_1- x thin fil m grown at the optimized temperature had the smoothest surface with lowest RMS v alue of 1.2 nm and TEM cross-sectional micrograph showing a well defined column ar structure.
基金Funded by National Natural Science Foundation of China(Nos.51102101,51272196,51372188,51521001)the 111 Project(No.B13035)+2 种基金the International Science&Technology Cooperation Program of China(No.2014DFA53090)the Natural Science Foundation of Hubei Province,China(No.2014CFB870)the Fundamental Research Funds for the Central Universities,China(No.WUT:2015III023)
文摘The CuxSi(1-x) thin films have been grown by pulsed laser deposition(PLD) with in situ annealing on Si(001) and Si(111),respectively.The transformation of phase was detected by X-ray diffraction(XRD).The results showed that the as-deposited films were composed of Cu on both Si(001) and Si(111).The annealed thin films consisted of Cu +η "-Cu3Si on Si(001) while Cu +η'-Cu3Si on Si(111),respectively,at annealed temperature(Ta)= 300-600℃.With the further increasing of Ta,at Ta= 700℃,there was only one main phase,η"-Cu3Si on Si(001) while η'-Cu3Si on Si(111),respectively.The annealed thin films transformed from continuous dense structure to scattered-grain morphology with increasing Ta detected by field emission scanning electron microscope(FESEM).It was also showed that the grain size would enlarge with increasing annealing time(ta).
文摘We present the results concerning photovoltaic materials CuIn1-xGaxSe2 thin films, which were obtained by close-spaced vapor transport “CSVT”. The influence of the iodine pressure on the growth of CuIn1-xGaxSe2 thin films was studied. The thin films were characterized by Energy Dispersive Spectrometry (EDS), Scanning Electron Microscope (SEM), hot point probe method, X-Ray Diffraction (XRD), Photoluminescence, and Optical response (Photoconductivity). At high pressure, the deposition rate was very important. The films were relatively thick and homogeneous with large grains dimensions. These films are formed of crystals placed in a preferential orientation depending on the plan (112). At low pressure, the films were thin and inhomogeneous with relatively small grains. These films of crystals didn’t have preferential orientation.
文摘Cadmium Cobalt Sulphide (CdxCo1-xS) thin film was deposited on microscopic glass substrate using chemical bath deposition technique at room temperature from aqueous solutions of Cadmium Chloride, Cobalt Chloride and Thiourea in which ammonium solution was used as complexing agents. The optical properties were characterized using the absorbance and transmission measurement from Unico UV-2102 PC spectrophotometer, at normal incidence of light in the wavelength range of 200 - 1000 nm. We report the deposition and optimization of the growth parameter with respect to time which showed that the band gap energy and the composition verified from the extended Vegard’s law are highly dependent on deposition time. The average transmittance of the film in VIS-NIR region ranges between 30% and 78% with absorbance range of 0.15 - 0.47 within the same wavelength range. The film was also observed to exhibit poor reflectance (11 x = 0.75;0.83 and 0.94), respectively. Other optical and dielectric properties of the films were also characterized. Based on the exhibited properties of the film, it can be concluded that it is a promising material for selective coatings for solar cells;effective coatings for poultry houses;use as antireflective coating materials, and for fabrication of optoelectronic devices.