ZnS films were successfully grown by metallorganic chemical vapour deposition (MOCVD) at atmospheric pressure on (100) GaAs substrates. The deposition was carried out at a substrate temperature between 280 approximate...ZnS films were successfully grown by metallorganic chemical vapour deposition (MOCVD) at atmospheric pressure on (100) GaAs substrates. The deposition was carried out at a substrate temperature between 280 approximately 550°C with optimisation of reactor design and growth conditions. The gas phase prereaction is effectively restrained. These epilayers exhibit high crystallographic quality and reveal a mirror surface morphology. The peak halfwidths of X-ray diffraction patterns from their (400) faces are within 0.06 approximately 0.09°. The epilayers grown on (111) GaAs, (112¯0) Al2O3 and (100) Si have proven to be single crystalline feature. The optical and electrical characteristics of ZnS epilayers are measured by photoluminescence, cathodeluminescence, and the Van der Pauw method. The results indicate that there are not a large number of deep centers that could be detected both at 77K and at room temperature. A broad CL peak around 2.897eV and 2.672eV was observed only under very strong excitation. Their origin has not been examined. All epilayers present high resistivities up to 1013Ω·cm.展开更多
ZnO quantum dots (QDs)with the sizes of 3.0-5.6 nm are synthesized by solution-phase method at different temperatures. We find that temperature has great influence on the size of ZnO QDs. The growth process is the mos...ZnO quantum dots (QDs)with the sizes of 3.0-5.6 nm are synthesized by solution-phase method at different temperatures. We find that temperature has great influence on the size of ZnO QDs. The growth process is the most sensitive to temperature, and the process is well explained by Lifshitz–Slyozov–Wagner (LSW) model. By photoluminescence (PL) spectra of the quantum dots at different temperatures and reactive time, we come to a conclusion that ultraviolet emission is mainly due to surface defects, and the or...展开更多
The synthesis of zinc oxide （ZnO） nanowires is achieved by vapor phase transportation （VPT） method. The designed quartz tube, whose both ends are narrow and the middle is wider, is used to control the growth of Zn...The synthesis of zinc oxide （ZnO） nanowires is achieved by vapor phase transportation （VPT） method. The designed quartz tube, whose both ends are narrow and the middle is wider, is used to control the growth of ZnO nanowires. Dielectrophoresis （DEP） method is employed to align and manipulate ZnO nanowires which are ultrasonic dispersed and suspended in ethanol solution. Under the dielectrophoretic force, the nanowires are trapped on the pre-patterned electrodes, and further aligned along the electric field and bridge the electrode gap. The dependence of the alignment yield on the applied voltage and frequency is investigated.展开更多
文摘ZnS films were successfully grown by metallorganic chemical vapour deposition (MOCVD) at atmospheric pressure on (100) GaAs substrates. The deposition was carried out at a substrate temperature between 280 approximately 550°C with optimisation of reactor design and growth conditions. The gas phase prereaction is effectively restrained. These epilayers exhibit high crystallographic quality and reveal a mirror surface morphology. The peak halfwidths of X-ray diffraction patterns from their (400) faces are within 0.06 approximately 0.09°. The epilayers grown on (111) GaAs, (112¯0) Al2O3 and (100) Si have proven to be single crystalline feature. The optical and electrical characteristics of ZnS epilayers are measured by photoluminescence, cathodeluminescence, and the Van der Pauw method. The results indicate that there are not a large number of deep centers that could be detected both at 77K and at room temperature. A broad CL peak around 2.897eV and 2.672eV was observed only under very strong excitation. Their origin has not been examined. All epilayers present high resistivities up to 1013Ω·cm.
基金supported in part by National Natural Science Foundation of China(Grant No.60877029)supported by the Tianjin Natural Science Foundation (Grant No.07JCYBJC0640006TXTJJC14600)supported by the Subject of Science and Technology Development Fund at University of Tianjin (Grant No.20071207)
文摘ZnO quantum dots (QDs)with the sizes of 3.0-5.6 nm are synthesized by solution-phase method at different temperatures. We find that temperature has great influence on the size of ZnO QDs. The growth process is the most sensitive to temperature, and the process is well explained by Lifshitz–Slyozov–Wagner (LSW) model. By photoluminescence (PL) spectra of the quantum dots at different temperatures and reactive time, we come to a conclusion that ultraviolet emission is mainly due to surface defects, and the or...
基金supported by the National Natural Science Foundation of China (No. 60725413, 60576008,and 10674023)the National "863" Program of China(No. 2006AA03Z313)the National "973" Program(No. 2007CB936300)
文摘The synthesis of zinc oxide （ZnO） nanowires is achieved by vapor phase transportation （VPT） method. The designed quartz tube, whose both ends are narrow and the middle is wider, is used to control the growth of ZnO nanowires. Dielectrophoresis （DEP） method is employed to align and manipulate ZnO nanowires which are ultrasonic dispersed and suspended in ethanol solution. Under the dielectrophoretic force, the nanowires are trapped on the pre-patterned electrodes, and further aligned along the electric field and bridge the electrode gap. The dependence of the alignment yield on the applied voltage and frequency is investigated.
