压电半导体ZnO单晶的Brillouin散射

本文导出了任意对称性压电半导体晶体中任意传播方向的声波方程,分析了对Brillouin散射有贡献的弹光效应、切变波引起的局部转动效应以及伴随准静电场产生的电光效应三种散射机制.给出了ZnO单晶热声子Brillouin散射谱,得到了ZnO单晶在室温下特高频段内全部5个独立弹性常数的值,发现比低频段的值约低45%;同时还确定了一组ZnO单晶的光弹系数关系式以及其xz平面准纵声波的倒速度曲线.

BRILLOUIN SCATTERING IN PIEZOELECTRIC SEMICONDUCTOR CRYSTAL ZnO

The derivation of the acoustic wave equation which is valid for piezoelectric semiconductor crystals of any symmetry and for any acoustic propagating direction is presented. Three mechanisms contributing to Brillouin scattering in high resistivity ZnO crystal are analysed. They are the elasto-optic effect, rotational contribution of shear wave and the electro-optic effect induced by the aocompaning potential. Thermal Brillouin scattering in ZnO crystal is performed. All of five independent elastic constants of ZnO crystal in high frequency range at room temperature are measured and the values are smaller than those reported in lower frequency by about 4.5%. Four photoelastio coefficient relations are given and the curve of the reciprocal velocity of quasi-longitudinal acoustic wave in x-z plane 10 depicted.