MnxCd1-xln2Te4 (x=0.1) ingot was successfully grown by the modified Bridgman technique, which applied the accelerated crucible rotation technique (ACRT) in Bridgman process, or briefly ACRT-B. The growth interface pro...MnxCd1-xln2Te4 (x=0.1) ingot was successfully grown by the modified Bridgman technique, which applied the accelerated crucible rotation technique (ACRT) in Bridgman process, or briefly ACRT-B. The growth interface profile shape and the composition distribution in the MnxCd1-xln2Te4 (x=0.1) ingot were analyzed. Even though the stoichiometric composition was synthesized in the original ingot, the composition has been redistributed during the ACRT-B growth process. Mn and Cd contents decrease while In increases along the longitudinal axis. The partition ratios of solutes Mn, Cd and In at the growth interface are evaluated by a mathematical method based on the experimental data, which are found to be 1.286, 1.926 and 0.729 in α phase growth process, and 1.120, 1.055 and 0.985 in β phase growth process, respectively. In the radial direction, Mn and Cd contents increase while In decreases with the distance from the centerline of the ingot.展开更多
The electronic and optical properties of the defect chalcopyrite CdGa2Te4 compound are studied based on the first- principles calculations. The band structure and density of states are calculated to discuss the electr...The electronic and optical properties of the defect chalcopyrite CdGa2Te4 compound are studied based on the first- principles calculations. The band structure and density of states are calculated to discuss the electronic properties and orbital hybridized properties of the compound. The optical properties, including complex dielectric function, absorption coefficient, refractive index, reflectivity, and loss function, and the origin of spectral peaks are analysed based on the electronic structures. The presented results exhibit isotropic behaviours in a low and a high energy range and an anisotropic behaviour in an intermediate energy range.展开更多
The Sb6 Te4/VO2 multilayer thin films are prepared by magnetron sputtering and the potential application in phase change memory is investigated in detail. Compared with Sb6 Te4, Sb6 Te4/VO2 multilayer composite thin f...The Sb6 Te4/VO2 multilayer thin films are prepared by magnetron sputtering and the potential application in phase change memory is investigated in detail. Compared with Sb6 Te4, Sb6 Te4/VO2 multilayer composite thin films have higher phase change temperature and crystallization resistance, indicating better thermal stability and less power consumption. Also, Sb6 Te4/VO2 has a broader energy band of 1.58 eV and better data retention （125℃ for 103/）. The crystallization is suppressed by the multilayer interfaces in Sbf Te4/VO2 thin film with a smaller rms surface roughness for Sbf Te4/VO2 than monolayer Sb4Te6. The picosecond laser technology is applied to study the phase change speed. A short crystallization time of 5.21 ns is realized for the Sb6Te4 （2nm）/VO2 （8nm） thin film. The Sb6 Te4/VO2 multilayer thin film is a potential and competitive phase change material for its good thermal stability and fast phase change speed.展开更多
The effect of annealing on microstructure, adhesive and frictional properties of GeSb2Te4 films were experimentally studied. The GeSb2Te4 films were prepared by radio frequency （RF） magnetron sputtering, and anneale...The effect of annealing on microstructure, adhesive and frictional properties of GeSb2Te4 films were experimentally studied. The GeSb2Te4 films were prepared by radio frequency （RF） magnetron sputtering, and annealed at 200℃ and 340℃ under vacuum circumstance, respectively. The adhesion and friction experiments were mainly conducted with a lateral force microscope （LFM） for the GeSb2Te4 thin films before and after annealing. Their morphology and phase structure were analyzed by using atomic force microscopy （AFM） and X-ray Diffraction （XRD） techniques, and the nanoindention was employed to evaluate their hardness values. Moreover, an electric force microscope （EFM） was used to measure the surface potential. It is found that the deposited GeSb2Te4 thin film undergoes an amorphous-to-fcc and fcc-to-hex structure transition; the adhesion has a weaker dependence on the surface roughness, but a certain correlation with the surface potential of GeSb2Te4 thin films. And the friction behavior of GeSb2Te4 thin films follows their adhesion behavior under a lower applied load. However, such a relation is replaced by the mechanical behavior when the load is relatively higher. Moreover, the GeSb2Te4 thin film annealed at 340℃ presents a lubricative property.展开更多
基金This research is supported by the National Natural Science Foundation of China under the contract No.59872027 and 59825109.
文摘MnxCd1-xln2Te4 (x=0.1) ingot was successfully grown by the modified Bridgman technique, which applied the accelerated crucible rotation technique (ACRT) in Bridgman process, or briefly ACRT-B. The growth interface profile shape and the composition distribution in the MnxCd1-xln2Te4 (x=0.1) ingot were analyzed. Even though the stoichiometric composition was synthesized in the original ingot, the composition has been redistributed during the ACRT-B growth process. Mn and Cd contents decrease while In increases along the longitudinal axis. The partition ratios of solutes Mn, Cd and In at the growth interface are evaluated by a mathematical method based on the experimental data, which are found to be 1.286, 1.926 and 0.729 in α phase growth process, and 1.120, 1.055 and 0.985 in β phase growth process, respectively. In the radial direction, Mn and Cd contents increase while In decreases with the distance from the centerline of the ingot.
基金Project supported by the Foundation for Key Program of Ministry of Education, China （Grant No. 212104） and the Foundation for University Young Core Instructors of Henan Province, China （Grant No. 2010GGJS-066）.
文摘The electronic and optical properties of the defect chalcopyrite CdGa2Te4 compound are studied based on the first- principles calculations. The band structure and density of states are calculated to discuss the electronic properties and orbital hybridized properties of the compound. The optical properties, including complex dielectric function, absorption coefficient, refractive index, reflectivity, and loss function, and the origin of spectral peaks are analysed based on the electronic structures. The presented results exhibit isotropic behaviours in a low and a high energy range and an anisotropic behaviour in an intermediate energy range.
基金Supported by the National Natural Science Foundation of China under Grant No 11774438the Natural Science Foundation of Jiangsu Province under Grant No BK20151172+2 种基金the Qing Lan Project,the Opening Project of State Key Laboratory of Silicon Materials under Grant No SKL2017-04the Opening Project of Key Laboratory of Microelectronic Devices and Integrated Technology of Chinese Academy of Sciencesthe Postgraduate Research and Practice Innovation Program of Jiangsu Province under Grant No SJCX18_1024
文摘The Sb6 Te4/VO2 multilayer thin films are prepared by magnetron sputtering and the potential application in phase change memory is investigated in detail. Compared with Sb6 Te4, Sb6 Te4/VO2 multilayer composite thin films have higher phase change temperature and crystallization resistance, indicating better thermal stability and less power consumption. Also, Sb6 Te4/VO2 has a broader energy band of 1.58 eV and better data retention （125℃ for 103/）. The crystallization is suppressed by the multilayer interfaces in Sbf Te4/VO2 thin film with a smaller rms surface roughness for Sbf Te4/VO2 than monolayer Sb4Te6. The picosecond laser technology is applied to study the phase change speed. A short crystallization time of 5.21 ns is realized for the Sb6Te4 （2nm）/VO2 （8nm） thin film. The Sb6 Te4/VO2 multilayer thin film is a potential and competitive phase change material for its good thermal stability and fast phase change speed.
基金the National Natural Science Foundation of China(No.50475124)the Foundation for the Author of National Excellent Doctoral Dissertation of China(No.200330)New Century Excellent Talents in University(NCET-04-0515)
文摘The effect of annealing on microstructure, adhesive and frictional properties of GeSb2Te4 films were experimentally studied. The GeSb2Te4 films were prepared by radio frequency （RF） magnetron sputtering, and annealed at 200℃ and 340℃ under vacuum circumstance, respectively. The adhesion and friction experiments were mainly conducted with a lateral force microscope （LFM） for the GeSb2Te4 thin films before and after annealing. Their morphology and phase structure were analyzed by using atomic force microscopy （AFM） and X-ray Diffraction （XRD） techniques, and the nanoindention was employed to evaluate their hardness values. Moreover, an electric force microscope （EFM） was used to measure the surface potential. It is found that the deposited GeSb2Te4 thin film undergoes an amorphous-to-fcc and fcc-to-hex structure transition; the adhesion has a weaker dependence on the surface roughness, but a certain correlation with the surface potential of GeSb2Te4 thin films. And the friction behavior of GeSb2Te4 thin films follows their adhesion behavior under a lower applied load. However, such a relation is replaced by the mechanical behavior when the load is relatively higher. Moreover, the GeSb2Te4 thin film annealed at 340℃ presents a lubricative property.
