采用分子束外延(Molecular Beam Epitaxy,MBE)法制备了高质量的npn型中波/中波双色HgCdTe材料。利用傅里叶变换红外光谱仪(Fourier Transform Infrared Spectrometer,FTIR)、二次离子质谱(Secondary Ion Mass Spectroscopy,SIMS)、X射...采用分子束外延(Molecular Beam Epitaxy,MBE)法制备了高质量的npn型中波/中波双色HgCdTe材料。利用傅里叶变换红外光谱仪(Fourier Transform Infrared Spectrometer,FTIR)、二次离子质谱(Secondary Ion Mass Spectroscopy,SIMS)、X射线双晶衍射仪(X-Ray double-crystal Diffractometer,XRD)分别测试了材料组分、厚度、元素分布和平均半峰宽等参数。结果表明,材料底部n型吸收层的碲镉汞组分为0.318,厚度为7.15 m;p型层的组分为0.392,厚度为2.47 m;顶部n型吸收层的组分为0.292,厚度为4.71 m。As掺杂浓度约为3×10^(18)cm^(-3),In掺杂浓度为4×10^(15)cm^(-3),平均半峰宽约为95 arcsec,表明该材料具有良好的质量。利用聚焦离子束(Focused Ion Beam,FIB)、扫描电子显微镜(Scanning Electron Microscope,SEM)、X射线能谱仪(Energy-Dispersive X-ray spectrometer,EDX)测试表征了HgCdTe外延材料表面缺陷的形貌,确认缺陷主要受生长温度和Hg/Te束流比等生长参数的影响。展开更多
The effect of In doping on the electronic structure and optical properties of SrTiO3 is investigated by the first-principles calculation of plane wave ultra-soft pseudo-potential based on the density function theory ...The effect of In doping on the electronic structure and optical properties of SrTiO3 is investigated by the first-principles calculation of plane wave ultra-soft pseudo-potential based on the density function theory (DFT). The calculated results reveal that due to the hole doping, the Fermi level shifts into valence bands (VBs) for SrTi1-x InxO3 with x = 0.125 and the system exhibits p-type degenerate semiconductor features. It is suggested according to the density of states (DOS) of SrTi0.875In0.125O3 that the band structure of p-type SrTIO3 can be described by a rigid band model. At the same time, the DOS shifts towards high energies and the optical band gap is broadened. The wide band gap, small transition probability and weak absorption due to the low partial density of states (PDOS) of impurity in the Fermi level result in the optical transparency of the film. The optical transmittance of In doped SrTiO3 is higher than 85% in a visible region, and the transmittance improves greatly. And the cut-off wavelength shifts into a blue-light region with the increase of In doping concentration.展开更多
Zinc oxide (ZnO) is one of the most promising and frequently used semiconductor materials. In-doped nanos- tructure ZnO thin films are grown on p-type gallium nitride substrates by employing the simultaneous rf and ...Zinc oxide (ZnO) is one of the most promising and frequently used semiconductor materials. In-doped nanos- tructure ZnO thin films are grown on p-type gallium nitride substrates by employing the simultaneous rf and dc magnetron co-sputtering technique. The effect of In-doping on structural, morphological and electrical properties is studied. The different dopant concentrations are accomplished by varying the direct current power of the In target while keeping the fixed radio frequency power of the ZnO target through the co-sputtering deposition technique by using argon as the sputtering gas at ambient temperature. The structural analysis confirms that all the grown thin films preferentially orientate along the c-axis with the wurtzite hexagonal crystal structure without having any kind of In oxide phases. The presenting Zn, 0 and In elements' chemical compositions are identified with EDX mapping analysis of the deposited thin films and the calculated M ratio has been found to decrease with the increasing In power. The surface topographies of the grown thin films are examined with the atomic force microscope technique. The obtained results reveal that the grown film roughness increases with the In power. The Hall measurements ascertain that all the grown films have n-type conductivity and also the other electrical parameters such as resistivity,mobility and carrier concentration are analyzed.展开更多
综述了近几年来亚波长陷光结构Hg Cd Te红外探测器研究进展.系统介绍了一种结合有限元方法与时域有限差分方法对红外探测器的"光""电"特性进行联合模拟和设计方法,以及基于这种新的数值模拟方法对亚波长人工微结构H...综述了近几年来亚波长陷光结构Hg Cd Te红外探测器研究进展.系统介绍了一种结合有限元方法与时域有限差分方法对红外探测器的"光""电"特性进行联合模拟和设计方法,以及基于这种新的数值模拟方法对亚波长人工微结构Hg Cd Te红外探测器的模拟和分析结果.理论分析和实验研制数据均显示这种新型亚波长人工微结构结构具有很好的陷光特性,在提高长波红外探测器性能方面具有潜在应用前景.展开更多
基金Project supported by the Natural Science Foundation of Shaanxi Province, China (Grant No 2005F06).
文摘The effect of In doping on the electronic structure and optical properties of SrTiO3 is investigated by the first-principles calculation of plane wave ultra-soft pseudo-potential based on the density function theory (DFT). The calculated results reveal that due to the hole doping, the Fermi level shifts into valence bands (VBs) for SrTi1-x InxO3 with x = 0.125 and the system exhibits p-type degenerate semiconductor features. It is suggested according to the density of states (DOS) of SrTi0.875In0.125O3 that the band structure of p-type SrTIO3 can be described by a rigid band model. At the same time, the DOS shifts towards high energies and the optical band gap is broadened. The wide band gap, small transition probability and weak absorption due to the low partial density of states (PDOS) of impurity in the Fermi level result in the optical transparency of the film. The optical transmittance of In doped SrTiO3 is higher than 85% in a visible region, and the transmittance improves greatly. And the cut-off wavelength shifts into a blue-light region with the increase of In doping concentration.
基金Supported by the RU Top-Down under Grant No 1001/CSS/870019
文摘Zinc oxide (ZnO) is one of the most promising and frequently used semiconductor materials. In-doped nanos- tructure ZnO thin films are grown on p-type gallium nitride substrates by employing the simultaneous rf and dc magnetron co-sputtering technique. The effect of In-doping on structural, morphological and electrical properties is studied. The different dopant concentrations are accomplished by varying the direct current power of the In target while keeping the fixed radio frequency power of the ZnO target through the co-sputtering deposition technique by using argon as the sputtering gas at ambient temperature. The structural analysis confirms that all the grown thin films preferentially orientate along the c-axis with the wurtzite hexagonal crystal structure without having any kind of In oxide phases. The presenting Zn, 0 and In elements' chemical compositions are identified with EDX mapping analysis of the deposited thin films and the calculated M ratio has been found to decrease with the increasing In power. The surface topographies of the grown thin films are examined with the atomic force microscope technique. The obtained results reveal that the grown film roughness increases with the In power. The Hall measurements ascertain that all the grown films have n-type conductivity and also the other electrical parameters such as resistivity,mobility and carrier concentration are analyzed.
文摘综述了近几年来亚波长陷光结构Hg Cd Te红外探测器研究进展.系统介绍了一种结合有限元方法与时域有限差分方法对红外探测器的"光""电"特性进行联合模拟和设计方法,以及基于这种新的数值模拟方法对亚波长人工微结构Hg Cd Te红外探测器的模拟和分析结果.理论分析和实验研制数据均显示这种新型亚波长人工微结构结构具有很好的陷光特性,在提高长波红外探测器性能方面具有潜在应用前景.