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采用低压金属有机化学气相沉积(LP-MOCVD)技术,两步生长法在InP衬底上制备In0.82Ga0.18As材料。研究缓冲层的生长温度对In0.82Ga0.18As薄膜的结构及电学性能的影响。固定外延薄膜的生长条件,仅改变缓冲层生长温度(分别为410,430,450,470℃),且维持缓冲层其他生长条件不变。用拉曼散射研究样品的结构性能,测量四个样品的拉曼散射光谱,得到样品的GaAs的纵向光学(LO)声子散射峰的非对称比分别为1.53,1.52,1.39和1.76。测量样品的霍耳效应表明,载流子浓度随缓冲层生长温度变化而改变,同时迁移率也随缓冲层生长温度变化而改变。通过实验得出:缓冲层的生长温度能够影响In0.82Ga0.18As薄膜的结构及电学性能。最佳的缓冲层生长温度为450℃。
The In0.82Ga0.18As material was prepared on InP substrate by low-pressure metal-organic chemical vapor deposition (LP-MOCVD) technique and two-step growth method. The influence of the growth temperature of buffer layer on the structure and electrical properties of In0.82Ga0.18As thin films was investigated. Fixed epitaxial film growth conditions, only changing the buffer layer growth temperature (410,430,450,470 ° C, respectively), and to maintain the buffer layer of other growth conditions unchanged. The Raman scattering spectra of four samples were measured by Raman scattering. The asymmetric ratios of the longitudinal optical (LO) phonon scattering peaks of GaAs were 1.53, 1.52, 1.39 and 1.76, respectively. The Hall effect of the measured samples shows that the carrier concentration changes with the growth temperature of the buffer layer, and the mobility also changes with the growth temperature of the buffer layer. The results show that the growth temperature of buffer layer can affect the structure and electrical properties of In0.82Ga0.18As thin films. The best buffer layer growth temperature is 450 ℃.