半导体超晶格子带间跃迁光吸收理论研究

Intersubband Transition Optical Absorption of Semiconductor Supperlattice

从理论上研究了半导体超晶格子带间跃迁的光吸收性质,以GaAs/AlxGa1-xAs超晶格为例进行数值计算,分析了该材料的吸收系数随入射光光子能量、光场强度和超晶格结构参量(阱宽,垒宽,势垒高)的变化关系·计算表明:随着入射光光子能量的变化,出现非对称的吸收峰;光强只改变吸收系数大小;超晶格结构参量会改变吸收谱的谱宽和吸收峰所对应的入射光频率·随着超晶格阱宽(垒宽)的增大,吸收谱由宽变窄,吸收峰红移;随着超晶格Al组分变大,吸收谱变窄·

The absorption induced by intersubband transition in semiconductor superlattice was studied. Numerical illustrations of the optical absorption in a GaAs/AlxGa1-xAs superlattice were given. The optical absorption coefficient as a function of the incident optical frequency, the optical intensity, the temperature and the structure parameters of superlattices （The width of quantum well, the barrier width and the composition percent of Al） were obtained. The simulation results showed that the absorption spectra of superlttice appeared as asymmetric absorption band. The optical intensity only changed the magnitude of absorption coefficient. The structure parameters of superlattice could change the width of absorption spectra and the resonant photon energy. The wider the well or barrier were,the narrower the absorption band became the smaller the center absorption band, the bigger was the absorption coefficients, and the absorption peak red shifted. The absorption band became narrow and the absorption coefficients increased when the composition percent of Al increased.