摘要
本文在考虑量子阱中轻重空穴混合效应的理论基础上,导出线偏振激光激发的热电子荧光的偏振度.结果和B.P.Zakharchenya等及D.N.Mirlin等最近采用的,直接从三维体材料理论移植过来的公式有很大的不同.本文进一步导出,存在无规化准弹性散射和有外加垂直磁场时,引起的附加退偏振因子.根据理论和实验的比较,可以求获LO-声子非弹性散射及无规化准弹性散射的时间常数.以文献中发表的一项实验结果为例,具体给出两种散射的时间常数.
Hot electrons excited from the valence band bY linearly polarized laser light are characteri-zed by certain angular distribution in momenta.Owing to such angular distribution in momenta,the photoluminescence from the hot electrons shows certain degree of polarization.A theoreticaltreatment of this effect observed in the photoluminescence in quantum wells is given, showingthat the effect depends strongly on heavy and light hole mixing.The very large disparity b-twe-en the experimentally observed and theoretically expected values of the degree of polarization inthe hot electron photoluminescence suggests the presence of random quasi-elastic scattering. Theeffects of such additional scattering and the presence of a perpendicular magnetic field are in-corporated into the theory.It is shown that the measurements of the degree of polarization obse-rved in the hot electron photoluminescence, with and without an applied perpendicular magneticfield can serve to determine the time constants for both LO-phonon inelastic and random qu-asi-elastic scattering.As an example, these time constants are determined for the experiments re-ported in the literature.
基金
国家自然科学基金
