液相外延GaAs1-xPx混晶的光学声子、等离子体激元和LO声子-等离子体激元耦合模

在40—700cm^-1波数和4.2—300K温度范围内研究了不同组份液相外延n型CaAs_1-xP_x样品的红外反射谱。对反射谱进行了赝谐振子拟合与K-K关系计算。从而获得了有关描述CaAs_1-xP_x样品的光学声子模、等离子体激元、LO声子-等离子体激元耦合模的重要物理参量及红外光学常数信息。基于这些计算结果,提出了双导带谷并计及与X能谷相联系的施主能级模型,用它解释等离子体激元频率和实验观察的三支主要的耦合模的温度变化规律。 关键词：

THE OPTICAL PHONONS, PLASMON AND LO PHONON-PLASMON COUPLING MODE IN MIXED CRYSTAL GaAs1-xPx GROWN BY LIQUID PHASE EPITAXY

The far infrared reflection spectra of n-GaAs_1-xP_x with x= 0.328 and x = 0.40 are investigated in the frequency range of 40-700 cm^-1 and the temperature range of 4.2-300 K. The important physical parameters describing the optical phonons, plasmon and LO phononplasmon coupling mode of the material and infrared optical constants are obtained by the multioscilla-tor fitting and K-K relation calculation. A model of two conduction band valley with a donor level below and associated with X minimum is presented to explain the behavior of the dependence of plasmon frequency on temperature and the variation of the three coupling modes with temperature.