Li-doped ZnO thin films had been grown by radio frequency magnetron sputtering and then annealed under various annealing temperatures. The characteristics of ZnO films were examined by XRD, FESEM, Hall measurement and...Li-doped ZnO thin films had been grown by radio frequency magnetron sputtering and then annealed under various annealing temperatures. The characteristics of ZnO films were examined by XRD, FESEM, Hall measurement and optical transmission spectra. Results showed that p type conduction was observed in Li doped ZnO films annealed at 500-600 ℃ and thep type ZnO films possessed a good crystalline with c-axis orientation, dense surface, and average transmission of about 85% in visible spectral region.展开更多
CdTe is one of the leading materials for low cost,high efficiency thin-film solar cells with a nearly ideal band gap of 1.48 eV.However,its solar to electricity power conversion efficiency(PCE)is hindered by the relat...CdTe is one of the leading materials for low cost,high efficiency thin-film solar cells with a nearly ideal band gap of 1.48 eV.However,its solar to electricity power conversion efficiency(PCE)is hindered by the relatively low open circuit voltage(VOC)due to intrinsic defect related issues.Here,we propose that alloying CdTe with CdSe could possibly improve the solar cell performance by reducing the"ideal"band gap of CdTe to gain more short-circuit current from long-wavelength absorption without sacrificing much VOC.Using the hybrid functional calculation,we find that the minimum band gap of the CdTe1-xSex alloy can be reduced from 1.48 eV at x=0 to 1.39 eV at x=0.32,and most of the change come from the lowering of the conduction band minimum.We also show that the formation of the alloy can improve the p-type doping of CuCdimpurity based on the reduced effective formation energy and nearly constant effective transition energy level,thus possibly enhance VOC,thus PCE.展开更多
With diethylamine as a solvent, ZnSe films were formed on the Si substrate directly from zinc and selenium through the modified solvothermal method. The effects of holding temperature, deposition time and substrate su...With diethylamine as a solvent, ZnSe films were formed on the Si substrate directly from zinc and selenium through the modified solvothermal method. The effects of holding temperature, deposition time and substrate surface treatment on the quality and morphologies of the ZnSe films were investigated. The growth mechanism of ZnSe films was proved to be a layer-nucleation growth process, which was tied in with the Stranski-Krastanov (SK) model. ZnSe films were identified by the X-ray diffraction pattern (XRD), the scanning electron microscope (SEM), the X-ray photoelectron spectroscope (XPS) and the photoluminescence (PL) techniques. The results indicate that the modified solvothermal method with diethylamine as a solvent is suitable to prepare high quality ZnSe films.展开更多
This paper reported the synthesis, crystal structure and electrical conductivity properties of Ni-doped ZnO powders (i.e. Zn1-xNixO binary system, X=0, 0.0025, 0.005, 0.0075 and in the range 0.01≤X〈0.15). I- phase...This paper reported the synthesis, crystal structure and electrical conductivity properties of Ni-doped ZnO powders (i.e. Zn1-xNixO binary system, X=0, 0.0025, 0.005, 0.0075 and in the range 0.01≤X〈0.15). I- phase samples, which were indexed as single phase with a hexagonal (wurtzite) structure in the Zn1-xNixO binary system, were determined by X-ray diffraction (XRD). The widest range of the I-phase was determined as 0≤X≤0.03 at 1200℃; above this range the mixed phase was observed. The impurity phase was determined as NiO when compared with standard XRD data, using the PDF program. We focused on single f-phase ZnO samples which were synthesized at 1200℃ because of the widest range of solubility limit at this temperature. It was observed that the lattice parameters a and c of the I-phase decreased with Ni doping concentration. The morphology of the I-phase samples was analyzed with a scanning electron microscope. The electrical conductivity of the pure ZnO and single I-phase samples were studied by using the four-probe dc method at temperatures between 100 and 950℃ in air atmosphere. The electrical conductivity values of pure ZnO and 3 mol% Ni-doped ZnO samples at 100℃C were 2×10^-6 and 4.8×10^-6 Ω-1.cm^-1, and at 950℃ they were 1.8 and 3.6 Ω-1cm-1, respectively. In other words, electrical conductivity increased with Ni doping concentration.展开更多
基金Funded by the Natural Science Foundation of Liaoning,China(No.201204916)Training Programme Foundation for the Talents by the Education Bureau of Liaoning Province,China(No.LJQ2013068)+1 种基金Key Program of Ministry of Education,China(No.212031)Liaoning College Creative Team(No.LT2013014)
文摘Li-doped ZnO thin films had been grown by radio frequency magnetron sputtering and then annealed under various annealing temperatures. The characteristics of ZnO films were examined by XRD, FESEM, Hall measurement and optical transmission spectra. Results showed that p type conduction was observed in Li doped ZnO films annealed at 500-600 ℃ and thep type ZnO films possessed a good crystalline with c-axis orientation, dense surface, and average transmission of about 85% in visible spectral region.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB0700700)the National Natural Science Foundation of China(Grant Nos.51672023,11847043,11634003,and U1530401)the Science Challenge Project(Grant Nos.TZ2016003 and TZ2018004)
文摘CdTe is one of the leading materials for low cost,high efficiency thin-film solar cells with a nearly ideal band gap of 1.48 eV.However,its solar to electricity power conversion efficiency(PCE)is hindered by the relatively low open circuit voltage(VOC)due to intrinsic defect related issues.Here,we propose that alloying CdTe with CdSe could possibly improve the solar cell performance by reducing the"ideal"band gap of CdTe to gain more short-circuit current from long-wavelength absorption without sacrificing much VOC.Using the hybrid functional calculation,we find that the minimum band gap of the CdTe1-xSex alloy can be reduced from 1.48 eV at x=0 to 1.39 eV at x=0.32,and most of the change come from the lowering of the conduction band minimum.We also show that the formation of the alloy can improve the p-type doping of CuCdimpurity based on the reduced effective formation energy and nearly constant effective transition energy level,thus possibly enhance VOC,thus PCE.
基金National Natural Science Foundation of China (50502028, 50336040)The Outstanding Youth Foundation of North-western Polytechnical University
文摘With diethylamine as a solvent, ZnSe films were formed on the Si substrate directly from zinc and selenium through the modified solvothermal method. The effects of holding temperature, deposition time and substrate surface treatment on the quality and morphologies of the ZnSe films were investigated. The growth mechanism of ZnSe films was proved to be a layer-nucleation growth process, which was tied in with the Stranski-Krastanov (SK) model. ZnSe films were identified by the X-ray diffraction pattern (XRD), the scanning electron microscope (SEM), the X-ray photoelectron spectroscope (XPS) and the photoluminescence (PL) techniques. The results indicate that the modified solvothermal method with diethylamine as a solvent is suitable to prepare high quality ZnSe films.
基金supported by the Research Foundation of Erciyes University (Kayseri,Turkey)
文摘This paper reported the synthesis, crystal structure and electrical conductivity properties of Ni-doped ZnO powders (i.e. Zn1-xNixO binary system, X=0, 0.0025, 0.005, 0.0075 and in the range 0.01≤X〈0.15). I- phase samples, which were indexed as single phase with a hexagonal (wurtzite) structure in the Zn1-xNixO binary system, were determined by X-ray diffraction (XRD). The widest range of the I-phase was determined as 0≤X≤0.03 at 1200℃; above this range the mixed phase was observed. The impurity phase was determined as NiO when compared with standard XRD data, using the PDF program. We focused on single f-phase ZnO samples which were synthesized at 1200℃ because of the widest range of solubility limit at this temperature. It was observed that the lattice parameters a and c of the I-phase decreased with Ni doping concentration. The morphology of the I-phase samples was analyzed with a scanning electron microscope. The electrical conductivity of the pure ZnO and single I-phase samples were studied by using the four-probe dc method at temperatures between 100 and 950℃ in air atmosphere. The electrical conductivity values of pure ZnO and 3 mol% Ni-doped ZnO samples at 100℃C were 2×10^-6 and 4.8×10^-6 Ω-1.cm^-1, and at 950℃ they were 1.8 and 3.6 Ω-1cm-1, respectively. In other words, electrical conductivity increased with Ni doping concentration.