By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped (Sr1-xLax)2IrO4 (001) (x=0, 0.05, 0.1 and 0.15) single crystalline thin films and then investigate the d...By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped (Sr1-xLax)2IrO4 (001) (x=0, 0.05, 0.1 and 0.15) single crystalline thin films and then investigate the doping dependence of the electronic structure utilizing in-situ angle-resolved photoemission spectroscopy. It is found that with the increasing doping content, the Fermi levels of samples progressively shift upward. Prominently, an extra electron pocket crossing the Fermi level around the M point is evidently observed in the 15% nominal doping sample. Moreover, bulk-sensitive transport measurements confirm that the doping effectively suppresses the insulating state with respect to the as-grown Sr2IrO4, though the doped samples still remain insulating at low temperatures due to the localization effect possibly stemming from disorders including oxygen deficiencies. Our work provides another feasible doping method to tune electronic structure of Sr2 IrO4.展开更多
Cu ion implantation and subsequent rapid annealing at 500℃ in N2 result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm2 V-1S-1 for microcrystalline diamond (MCD) films. Its electrical field...Cu ion implantation and subsequent rapid annealing at 500℃ in N2 result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm2 V-1S-1 for microcrystalline diamond (MCD) films. Its electrical field emission behavior can be turned on at Eo = 2.6 V/μm, attaining a current density of 19.5μA/cm2 at an applied field of 3.5 V/#m. Field emission scanning electron microscopy combined with Raman and x-ray photoelectron mi- croscopy reveal that the formation of Cu nanoparticles in MCD films can catalytically convert the less conducting disorder/a-C phases into graphitic phases and can provoke the formation of nanographite in the films, forming conduction channels for electron transportation.展开更多
We investigated the effects of using different thicknesses of pure and vanadium-doped thin films of TiO2 as the electron transport layer in the inverted configuration of organic photovoltaic cells based on poly(3-hex...We investigated the effects of using different thicknesses of pure and vanadium-doped thin films of TiO2 as the electron transport layer in the inverted configuration of organic photovoltaic cells based on poly(3-hexylthiophene) P3HT:[6-6] phenyl-(6) butyric acid methyl ester(PCBM). 1% vanadium-doped TiO2nanoparticles were synthesized via the solvothermal method. Crystalline structure, morphology, and optical properties of pure and vanadium-doped TiO2 thin films were studied by different techniques such as x-ray diffraction, scanning electron microscopy, transmittance electron microscopy, and UV–visible transmission spectrum. The doctor blade method which is compatible with roll-2-roll printing was used for deposition of pure and vanadium-doped TiO2 thin films with thicknesses of 30 nm and 60 nm. The final results revealed that the best thickness of TiO2 thin films for our fabricated cells was 30 nm. The cell with vanadium-doped TiO2 thin film showed slightly higher power conversion efficiency and great Jsc of 10.7 mA/cm^2 compared with its pure counterpart. In the cells using 60 nm pure and vanadium-doped TiO2 layers, the cell using the doped layer showed much higher efficiency. It is remarkable that the external quantum efficiency of vanadium-doped TiO2 thin film was better in all wavelengths.展开更多
Microwave electron cyclotron resonance plasma enhanced chemical vapor depositionwas used to grow silicon dioxide films on crystalline silicon substrate for planar optical waveguides.The relationship between plasma par...Microwave electron cyclotron resonance plasma enhanced chemical vapor depositionwas used to grow silicon dioxide films on crystalline silicon substrate for planar optical waveguides.The relationship between plasma parameters and deposition rates was investigated, and the influ-ence of radio frequency substrate bias on properties of SiO2 films was also preliminarily studied.X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron mi-croscopy, atomic force microscopy and elllipsometry were used to characterize the deposited films,showing that SiO2 films with good structural and optical properties prepared at low temperaturehave been achieved. They can basically meet the requirements of integrated optical waveguides.展开更多
a-C:F films are deposited by microwave electron cyclotron resonance (ECR)plasma chemical vapor deposition (CVD) using trifluoromethane (CHF3) and benzene (C6H6) as source gases at different microwave powers. The radic...a-C:F films are deposited by microwave electron cyclotron resonance (ECR)plasma chemical vapor deposition (CVD) using trifluoromethane (CHF3) and benzene (C6H6) as source gases at different microwave powers. The radicals in plasma originating from source gases dissociation are analyzed by relative irradiance measurement. The bonding configurations and binding state of a-C:F films are measured with Fourier-transformed infrared spectrometer (FTIR) and x-ray photoelectron spectroscopy (XPS). The results show that a-C:F films are mainly composed of CF radical at lower powers but of CF2 radical at higher powers. The deposition of films is related to the radicals generated in plasma and the main bonding configurations are dependent on the ratio of CF to CF2 radicals in films.展开更多
Effects of nonparabolicity of energy band on thermopower, in-plane effective mass and Fermi energy are inves- tigated in size-quantized semiconductor films in a strong while non-quantized magnetic field. We obtain the...Effects of nonparabolicity of energy band on thermopower, in-plane effective mass and Fermi energy are inves- tigated in size-quantized semiconductor films in a strong while non-quantized magnetic field. We obtain the expressions of these quantities as functions of thickness, concentration and nonparabolicity parameter. The influence of nonparabolicity is studied for degenerate and non-degenerate electron gases, and it is shown that nonparabolicity changes the character of thickness and the concentration dependence of thermopower, in-plane effective mass and Fermi energy. Moreover, the magnitudes of these quantities significantly increase with respect to the nonparabolicity parameter in the case of strong nonparabolicity in nano-films. The concentration depen- dence is also studied, and it is shown that thermopower increases when the concentration decreases. These results are in agreement with the experimental data.展开更多
We investigate the electronic-transport properties of two-dimensional monolayer films from Au-P-Au molecular junction to Au-Si-Au molecular junction using elastic scattering Green's function theory. In the process of...We investigate the electronic-transport properties of two-dimensional monolayer films from Au-P-Au molecular junction to Au-Si-Au molecular junction using elastic scattering Green's function theory. In the process of replacing the P atoms with Si atoms every other line from the middle of monolayer blue phosphorus molecular structure, the substitution of Si atoms changes the properties of Au-P-Au molecular junction significantly. Interestingly, the current value has a symmetric change as a parabolic curve with the peak appearing in Au-Si_1P_1-Au molecular junction, which provides the most stable current of 15.00 nA in a wide voltage range of 0.70-2.70 V.Moreover, the current-voltage characteristics of the structures indicate that the steps tend to disappear revealing the property similar to metal when the Si atoms dominate the molecular junction.展开更多
Iron-nitride films were prepared by reactive sputtering, and the effect of annealing treatment on the structures was investigated by means of in-situ electron microscopy and high resolution electron microscopy (HREM)....Iron-nitride films were prepared by reactive sputtering, and the effect of annealing treatment on the structures was investigated by means of in-situ electron microscopy and high resolution electron microscopy (HREM). As-deposited films were observed to be a mixed structure of a few ultrafine epsilon-Fe2-3N particles existing in the amorphous matrix. it was found that the structure-relaxation in the amorphous occurred at 473 K, and the ultrafine grains began to grow at the higher annealing temperatures. The transition of the amorphous to epsilon-Fe2-3N was almost completed at 673 K. It is considered that the formation of the ideal epsilon-Fe3N is originated from the ordering of the nitrogen atoms during the annealing in vacuum. On the other hand, gamma'-phase (Fe4N) was seen to precipitation of epsilon-phase at 723 K. Two possible modes are proposed in the precipitation of gamma'-phase, depending on the heating rate and crystallographic orientation relationships, i.e. [121](epsilon)//[001](gamma), (2(1) over bar0$)(epsilon)//(110)(gamma) and [100](epsilon)//[110](gamma), (001)(epsilon)//(111)(gamma). In addition, alpha-Fe particles were observed to form from the gamma'-phase at high temperatures. We assumed that these structural changes are due to the diffusion of nitrogen and iron atoms during the annealing, except for the case of the precipitation of the gamma'-phase as depicted above. The results obtained in this work are in a good agreement with the assumption.展开更多
We present the specific ab-initio calculations that detail the variations of perovskite BaZrO3 caused by in-plane strain. Specifically, the internal relaxation, which was not captured in the widely used biaxial strain...We present the specific ab-initio calculations that detail the variations of perovskite BaZrO3 caused by in-plane strain. Specifically, the internal relaxation, which was not captured in the widely used biaxial strain model, was included in a complementary manner to lattice relaxation. Density functional theory as well as a hybrid functional method based on a plane wave basis set was employed to calculate the lattice structure, elastic constants, electronic properties and optical properties of perovskite BaZrO3. The lattice parameter c exhibited a clear linear dependence on the imposed in-plane strain, but the Poisson's ratio caused by internal relaxation was smaller than the elastic deformation, indicating an "inelastic" or "plastic" relaxation manner caused by the introduction of internal relaxation. As a result, the related electronic and optical properties of perovskite BaZrO3 were also strongly affected by the in-plane strain, which revealed an effective way to adjust the properties of perovskite BaZrO3 via internal relaxation.展开更多
The continuous progress in thin film materials and devices has greatly promoted the development in the field of flexible electronics. As one of the most common thin film devices, thin film transistors(TFTs) are sign...The continuous progress in thin film materials and devices has greatly promoted the development in the field of flexible electronics. As one of the most common thin film devices, thin film transistors(TFTs) are significant building blocks for flexible platforms. Flexible oxide-based TFTs are well compatible with flexible electronic systems due to low process temperature, high carrier mobility, and good uniformity. The present article is a review of the recent progress and major trends in the field of flexible oxide-based thin film transistors. First, an introduction of flexible electronics and flexible oxide-based thin film transistors is given. Next, we introduce oxide semiconductor materials and various flexible oxide-based TFTs classified by substrate materials including polymer plastics, paper sheets, metal foils, and flexible thin glass. Afterwards, applications of flexible oxide-based TFTs including bendable sensors, memories, circuits, and displays are presented. Finally, we give conclusions and a prospect for possible development trends.展开更多
The aim of this work was to study the degradation behavior of Ti-6Al-4V alloys for dental applications in acidic artificial saliva with fluoride ion using electrochemical techniques, optical microscopy, scanning elect...The aim of this work was to study the degradation behavior of Ti-6Al-4V alloys for dental applications in acidic artificial saliva with fluoride ion using electrochemical techniques, optical microscopy, scanning electron microscopy(SEM), and energy dispersive spectrometry(EDS). The experimental results showed that fluoride ion had significant influence on the degradation of Ti-6Al-4V alloys, and there was an obvious critical concentration of fluoride ion(about 0.1wt%). With increasing fluoride ion concentration, the corrosion potential(Ecorr) of alloys moved toward negative and the impedance of alloys decreased, meanwhile, noticeable transformation from minimum corrosion to severe pitting corrosion was observed on alloys surface following the dissolution of TiO2 passive films, leading to the decrease of the corrosion resistance of alloys. The electrochemical dissolution of TiO2 passive films involved a nucleophilic attack of fluoride atom to the titanium atom of TiO2. In addition, Ca^(2+)and Na~+ in acidic saliva may involve the surface reactions and make the reactions more complex.展开更多
ZnSO4-Zn(CH3COO)2, Zn(NO3)2-Zn(CH3COO)2, ZnSO4-Zn(NO3)2, ZnSO4, Zn(NO3)2 or Zn(CH3COO)2 have been used as zinc sources to prepare ZnS thin films by chemical bath deposition and co-deposition methods. Zn(...ZnSO4-Zn(CH3COO)2, Zn(NO3)2-Zn(CH3COO)2, ZnSO4-Zn(NO3)2, ZnSO4, Zn(NO3)2 or Zn(CH3COO)2 have been used as zinc sources to prepare ZnS thin films by chemical bath deposition and co-deposition methods. Zn(NO3)2 or/and Zn(CH3COO)2 is/are favorable for cluster by cluster deposition process while ZnSO4 favors ion by ion deposition process regardless of concentration ratios of ZnSO4. However, Zn(NO3)2 affects the nucleation density of ZnS nuclei on the substrate. ZnS thin films deposited from ZnSO4-Zn(CH3COO)2 are not only more homogeneous and compact, but also have higher growth rate and adhesion on to the glass substrate. The cubic ZnS films are obtained after only single deposition. The average transmission of films from S6, S7, S8, S9 and S1 for 2 and 2.5 h is greater than 85% in visible region. Compared with the film from S6 (112 nm), the film from S7 is not only thicker (125 nm), but also more transparent. The band gaps of the films deposited from S6,S7, S8, S9 and S1 for 2 and 2.5 h range from 3.88 to 3.98 eV. The effects of anions from different zinc salts are discussed in detail.展开更多
Aberration-corrected scanning transmission electron microscopy was employed to investigate the microstructures and secondary phases in LaBaCo2O5.5+δ(LBCO) thin films grown on SrTiO3 (STO) substrates. The as-grow...Aberration-corrected scanning transmission electron microscopy was employed to investigate the microstructures and secondary phases in LaBaCo2O5.5+δ(LBCO) thin films grown on SrTiO3 (STO) substrates. The as-grown films showed an epitaxial growth on the substrates with atomically sharp interfaces and orientation relationships of [100]LBCO//[100]STO and (001)LBCO//(001)STO. Secondary phases were observed in the films, which strongly depended on the sample fabrication conditions. In the film prepared at a temperature of 900 ℃, nano-scale CoO pillars nucleated on the substrate, and grew along the [001] direction of the film. In the film grown at a temperature of 1000 ℃, isolated nano-scale C0304 particles appeared, which promoted the growth of {111 } twinning structures in the film. The orientation relationships and the interfaces between the secondary phases and the films were illustrated, and the growth mechanism of the film was discussed.展开更多
Ga doped ZnO (OZO)/Cu grid/GZO transparent conductive electrode (TCE) structures were fabricated at room temperature (RT) by using electron beam evaporation (EBE) for the Cu grids and RF magnetron sputtering f...Ga doped ZnO (OZO)/Cu grid/GZO transparent conductive electrode (TCE) structures were fabricated at room temperature (RT) by using electron beam evaporation (EBE) for the Cu grids and RF magnetron sputtering for the GZO layers. In this work, we investigated the electrical and optical characteristics of GZO/Cu grid/GZO multilayer electrode for thin film solar cells by using evaporated Cu grid and sputtered GZO thin films to enhance the optical transparency without significantly affecting their conductivity. The optical transmittance and sheet resistance of GZO/Cu grid/GZO multilayer are higher than those of GZO/Cu film/GZO multilayer independent of Cu grid separation distance and increase with increasing Cu grid separation distances. The calculation of both transmittance and sheet resistance of GZO/Cu grid] GZO multilayer was based on Cu filling factor correlated with the geometry of Cu grid. The calculated values for the transmittance and sheet resistance of the GZO/Cu grid/GZO multilayer were similar to the experimentally observed ones. The highest figure of merit ФTc is 5.18× 10^-3Ω^-1 for the GZO/Cu grid] GZO multilayer with Cu grid separation distance of 1 mm was obtained, in this case, the transmittance and resistivity were 82.72% and 2.17 × 10 ^-4Ωcm, respectively. The transmittance and resistivity are accentahle for nractical thin film snlar cell annlicatinn~展开更多
基金Supported by the National Basic Research Program of China(973 Program)under Grant Nos 2011CBA00106 and2012CB927400the National Natural Science Foundation of China under Grant Nos 11274332 and 11227902Helmholtz Association through the Virtual Institute for Topological Insulators(VITI).M.Y.Li and D.W.Shen are also supported by the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB04040300
文摘By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped (Sr1-xLax)2IrO4 (001) (x=0, 0.05, 0.1 and 0.15) single crystalline thin films and then investigate the doping dependence of the electronic structure utilizing in-situ angle-resolved photoemission spectroscopy. It is found that with the increasing doping content, the Fermi levels of samples progressively shift upward. Prominently, an extra electron pocket crossing the Fermi level around the M point is evidently observed in the 15% nominal doping sample. Moreover, bulk-sensitive transport measurements confirm that the doping effectively suppresses the insulating state with respect to the as-grown Sr2IrO4, though the doped samples still remain insulating at low temperatures due to the localization effect possibly stemming from disorders including oxygen deficiencies. Our work provides another feasible doping method to tune electronic structure of Sr2 IrO4.
基金Supported by the National Natural Science Foundation of China under Grant No 11405114the Natural Science Foundation of Shanxi Province under Grant No 2015021065
文摘Cu ion implantation and subsequent rapid annealing at 500℃ in N2 result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm2 V-1S-1 for microcrystalline diamond (MCD) films. Its electrical field emission behavior can be turned on at Eo = 2.6 V/μm, attaining a current density of 19.5μA/cm2 at an applied field of 3.5 V/#m. Field emission scanning electron microscopy combined with Raman and x-ray photoelectron mi- croscopy reveal that the formation of Cu nanoparticles in MCD films can catalytically convert the less conducting disorder/a-C phases into graphitic phases and can provoke the formation of nanographite in the films, forming conduction channels for electron transportation.
文摘We investigated the effects of using different thicknesses of pure and vanadium-doped thin films of TiO2 as the electron transport layer in the inverted configuration of organic photovoltaic cells based on poly(3-hexylthiophene) P3HT:[6-6] phenyl-(6) butyric acid methyl ester(PCBM). 1% vanadium-doped TiO2nanoparticles were synthesized via the solvothermal method. Crystalline structure, morphology, and optical properties of pure and vanadium-doped TiO2 thin films were studied by different techniques such as x-ray diffraction, scanning electron microscopy, transmittance electron microscopy, and UV–visible transmission spectrum. The doctor blade method which is compatible with roll-2-roll printing was used for deposition of pure and vanadium-doped TiO2 thin films with thicknesses of 30 nm and 60 nm. The final results revealed that the best thickness of TiO2 thin films for our fabricated cells was 30 nm. The cell with vanadium-doped TiO2 thin film showed slightly higher power conversion efficiency and great Jsc of 10.7 mA/cm^2 compared with its pure counterpart. In the cells using 60 nm pure and vanadium-doped TiO2 layers, the cell using the doped layer showed much higher efficiency. It is remarkable that the external quantum efficiency of vanadium-doped TiO2 thin film was better in all wavelengths.
文摘Microwave electron cyclotron resonance plasma enhanced chemical vapor depositionwas used to grow silicon dioxide films on crystalline silicon substrate for planar optical waveguides.The relationship between plasma parameters and deposition rates was investigated, and the influ-ence of radio frequency substrate bias on properties of SiO2 films was also preliminarily studied.X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron mi-croscopy, atomic force microscopy and elllipsometry were used to characterize the deposited films,showing that SiO2 films with good structural and optical properties prepared at low temperaturehave been achieved. They can basically meet the requirements of integrated optical waveguides.
文摘a-C:F films are deposited by microwave electron cyclotron resonance (ECR)plasma chemical vapor deposition (CVD) using trifluoromethane (CHF3) and benzene (C6H6) as source gases at different microwave powers. The radicals in plasma originating from source gases dissociation are analyzed by relative irradiance measurement. The bonding configurations and binding state of a-C:F films are measured with Fourier-transformed infrared spectrometer (FTIR) and x-ray photoelectron spectroscopy (XPS). The results show that a-C:F films are mainly composed of CF radical at lower powers but of CF2 radical at higher powers. The deposition of films is related to the radicals generated in plasma and the main bonding configurations are dependent on the ratio of CF to CF2 radicals in films.
文摘Effects of nonparabolicity of energy band on thermopower, in-plane effective mass and Fermi energy are inves- tigated in size-quantized semiconductor films in a strong while non-quantized magnetic field. We obtain the expressions of these quantities as functions of thickness, concentration and nonparabolicity parameter. The influence of nonparabolicity is studied for degenerate and non-degenerate electron gases, and it is shown that nonparabolicity changes the character of thickness and the concentration dependence of thermopower, in-plane effective mass and Fermi energy. Moreover, the magnitudes of these quantities significantly increase with respect to the nonparabolicity parameter in the case of strong nonparabolicity in nano-films. The concentration depen- dence is also studied, and it is shown that thermopower increases when the concentration decreases. These results are in agreement with the experimental data.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11374033,11774030,51735001 and 61775016the Fundamental Research Funds for the Central Universities under Grant No 2017CX10007
文摘We investigate the electronic-transport properties of two-dimensional monolayer films from Au-P-Au molecular junction to Au-Si-Au molecular junction using elastic scattering Green's function theory. In the process of replacing the P atoms with Si atoms every other line from the middle of monolayer blue phosphorus molecular structure, the substitution of Si atoms changes the properties of Au-P-Au molecular junction significantly. Interestingly, the current value has a symmetric change as a parabolic curve with the peak appearing in Au-Si_1P_1-Au molecular junction, which provides the most stable current of 15.00 nA in a wide voltage range of 0.70-2.70 V.Moreover, the current-voltage characteristics of the structures indicate that the steps tend to disappear revealing the property similar to metal when the Si atoms dominate the molecular junction.
文摘Iron-nitride films were prepared by reactive sputtering, and the effect of annealing treatment on the structures was investigated by means of in-situ electron microscopy and high resolution electron microscopy (HREM). As-deposited films were observed to be a mixed structure of a few ultrafine epsilon-Fe2-3N particles existing in the amorphous matrix. it was found that the structure-relaxation in the amorphous occurred at 473 K, and the ultrafine grains began to grow at the higher annealing temperatures. The transition of the amorphous to epsilon-Fe2-3N was almost completed at 673 K. It is considered that the formation of the ideal epsilon-Fe3N is originated from the ordering of the nitrogen atoms during the annealing in vacuum. On the other hand, gamma'-phase (Fe4N) was seen to precipitation of epsilon-phase at 723 K. Two possible modes are proposed in the precipitation of gamma'-phase, depending on the heating rate and crystallographic orientation relationships, i.e. [121](epsilon)//[001](gamma), (2(1) over bar0$)(epsilon)//(110)(gamma) and [100](epsilon)//[110](gamma), (001)(epsilon)//(111)(gamma). In addition, alpha-Fe particles were observed to form from the gamma'-phase at high temperatures. We assumed that these structural changes are due to the diffusion of nitrogen and iron atoms during the annealing, except for the case of the precipitation of the gamma'-phase as depicted above. The results obtained in this work are in a good agreement with the assumption.
基金Funded by the National Natural Science Foundation of China(No.51502179)the Colleges and Universities in Hebei Province Science and Technology Research Project(No.YQ2014033)the Hebei Key Discipline Construction Project(B2012210004 and E2013210038)
文摘We present the specific ab-initio calculations that detail the variations of perovskite BaZrO3 caused by in-plane strain. Specifically, the internal relaxation, which was not captured in the widely used biaxial strain model, was included in a complementary manner to lattice relaxation. Density functional theory as well as a hybrid functional method based on a plane wave basis set was employed to calculate the lattice structure, elastic constants, electronic properties and optical properties of perovskite BaZrO3. The lattice parameter c exhibited a clear linear dependence on the imposed in-plane strain, but the Poisson's ratio caused by internal relaxation was smaller than the elastic deformation, indicating an "inelastic" or "plastic" relaxation manner caused by the introduction of internal relaxation. As a result, the related electronic and optical properties of perovskite BaZrO3 were also strongly affected by the in-plane strain, which revealed an effective way to adjust the properties of perovskite BaZrO3 via internal relaxation.
基金supported in part by the National Science Foundation for Distinguished Young Scholars of China(No.61425020)in part by the National Natural Science Foundation of China(No.11674162)
文摘The continuous progress in thin film materials and devices has greatly promoted the development in the field of flexible electronics. As one of the most common thin film devices, thin film transistors(TFTs) are significant building blocks for flexible platforms. Flexible oxide-based TFTs are well compatible with flexible electronic systems due to low process temperature, high carrier mobility, and good uniformity. The present article is a review of the recent progress and major trends in the field of flexible oxide-based thin film transistors. First, an introduction of flexible electronics and flexible oxide-based thin film transistors is given. Next, we introduce oxide semiconductor materials and various flexible oxide-based TFTs classified by substrate materials including polymer plastics, paper sheets, metal foils, and flexible thin glass. Afterwards, applications of flexible oxide-based TFTs including bendable sensors, memories, circuits, and displays are presented. Finally, we give conclusions and a prospect for possible development trends.
基金Funded by the National Natural Science Foundation of China(No.50801057)the National Basic Research Priorities Program of China(No.2005DKA10400-CT-1-08-06)+1 种基金the Special Fund for Basic Scientific Research of Central Colleges,China University of Geosciences(Wuhan)(No.007-G1323521109)the National Natural Science Fundation of China(81641035 and 81401524)
文摘The aim of this work was to study the degradation behavior of Ti-6Al-4V alloys for dental applications in acidic artificial saliva with fluoride ion using electrochemical techniques, optical microscopy, scanning electron microscopy(SEM), and energy dispersive spectrometry(EDS). The experimental results showed that fluoride ion had significant influence on the degradation of Ti-6Al-4V alloys, and there was an obvious critical concentration of fluoride ion(about 0.1wt%). With increasing fluoride ion concentration, the corrosion potential(Ecorr) of alloys moved toward negative and the impedance of alloys decreased, meanwhile, noticeable transformation from minimum corrosion to severe pitting corrosion was observed on alloys surface following the dissolution of TiO2 passive films, leading to the decrease of the corrosion resistance of alloys. The electrochemical dissolution of TiO2 passive films involved a nucleophilic attack of fluoride atom to the titanium atom of TiO2. In addition, Ca^(2+)and Na~+ in acidic saliva may involve the surface reactions and make the reactions more complex.
基金the financial support of the National Natural Science Foundation of China (No. 50963003)the Natural Science Foundation of Jiangxi Province (No. 2010GZC0044)+1 种基金the Foundation of Jiangxi Educational Commission (No. GJJ14558)the Project of Jiangxi Youth Scientist (No. 20122BCB23031)
文摘ZnSO4-Zn(CH3COO)2, Zn(NO3)2-Zn(CH3COO)2, ZnSO4-Zn(NO3)2, ZnSO4, Zn(NO3)2 or Zn(CH3COO)2 have been used as zinc sources to prepare ZnS thin films by chemical bath deposition and co-deposition methods. Zn(NO3)2 or/and Zn(CH3COO)2 is/are favorable for cluster by cluster deposition process while ZnSO4 favors ion by ion deposition process regardless of concentration ratios of ZnSO4. However, Zn(NO3)2 affects the nucleation density of ZnS nuclei on the substrate. ZnS thin films deposited from ZnSO4-Zn(CH3COO)2 are not only more homogeneous and compact, but also have higher growth rate and adhesion on to the glass substrate. The cubic ZnS films are obtained after only single deposition. The average transmission of films from S6, S7, S8, S9 and S1 for 2 and 2.5 h is greater than 85% in visible region. Compared with the film from S6 (112 nm), the film from S7 is not only thicker (125 nm), but also more transparent. The band gaps of the films deposited from S6,S7, S8, S9 and S1 for 2 and 2.5 h range from 3.88 to 3.98 eV. The effects of anions from different zinc salts are discussed in detail.
基金financially supported by the National Natural Science Foundation of China (Nos. 51501143, 51202185 and 51390472)the National Basic Research Program of China (No. 2015CB654903)Fundamental Research Funds for the Central Universities, China Postdoctoral Science Foundation (No. 2015M572554)
文摘Aberration-corrected scanning transmission electron microscopy was employed to investigate the microstructures and secondary phases in LaBaCo2O5.5+δ(LBCO) thin films grown on SrTiO3 (STO) substrates. The as-grown films showed an epitaxial growth on the substrates with atomically sharp interfaces and orientation relationships of [100]LBCO//[100]STO and (001)LBCO//(001)STO. Secondary phases were observed in the films, which strongly depended on the sample fabrication conditions. In the film prepared at a temperature of 900 ℃, nano-scale CoO pillars nucleated on the substrate, and grew along the [001] direction of the film. In the film grown at a temperature of 1000 ℃, isolated nano-scale C0304 particles appeared, which promoted the growth of {111 } twinning structures in the film. The orientation relationships and the interfaces between the secondary phases and the films were illustrated, and the growth mechanism of the film was discussed.
基金support of the key project of the National Natural Science Foundation of China under Grant Nos.91333203 and 51172204the Program for Innovative Research Team in University of Ministry of Education of China under Grant No.IRT13037the Zhejiang Provincial Department of Science and Technology of China under Grant No.2010R50020
文摘Ga doped ZnO (OZO)/Cu grid/GZO transparent conductive electrode (TCE) structures were fabricated at room temperature (RT) by using electron beam evaporation (EBE) for the Cu grids and RF magnetron sputtering for the GZO layers. In this work, we investigated the electrical and optical characteristics of GZO/Cu grid/GZO multilayer electrode for thin film solar cells by using evaporated Cu grid and sputtered GZO thin films to enhance the optical transparency without significantly affecting their conductivity. The optical transmittance and sheet resistance of GZO/Cu grid/GZO multilayer are higher than those of GZO/Cu film/GZO multilayer independent of Cu grid separation distance and increase with increasing Cu grid separation distances. The calculation of both transmittance and sheet resistance of GZO/Cu grid] GZO multilayer was based on Cu filling factor correlated with the geometry of Cu grid. The calculated values for the transmittance and sheet resistance of the GZO/Cu grid/GZO multilayer were similar to the experimentally observed ones. The highest figure of merit ФTc is 5.18× 10^-3Ω^-1 for the GZO/Cu grid] GZO multilayer with Cu grid separation distance of 1 mm was obtained, in this case, the transmittance and resistivity were 82.72% and 2.17 × 10 ^-4Ωcm, respectively. The transmittance and resistivity are accentahle for nractical thin film snlar cell annlicatinn~