光激励下的半导体纳米材料中杂质对超声的吸收研究

研究了在激光场中晶格振动与杂质核相互作用下,具有无限势垒量子阱结构半导体中的超声衰减问题.电子吸收声子不能从受体杂质能"带"跃迁到第一量子能级导带,但在高频激光场中却会发生,激光场补充电子跃迁吸收声子所需能量.对总超声吸收系数进行了推算,并将此结果应用到纳米砷化镓(GaAs/AlGaAs)量子阱样品中,发现其总吸声系数比相应的传统物质的吸收系数大得多.

Photostimulated impurity absorption of ultrasound in semiconductor nanostructures

The problem of ultrasound attenuation in the semiconductor which has a quantum well structure with infinite potential barriers has been studied,in the case of the acoustic lattice vibrations interacting with impurity centers in the presence of an exciting laser field. The electron transitions from an acceptor- impurity "band" to the first quantized energy level of the conduction band occurs in the external laser field,which is forbidden in the absence of the external high frequency field,and the external laser field supply the energy deficit for the electron to make the transition to absorb the acoustic phonon.The total ultrasound absorption coefficient  has been calculated by applying second-order perturbation theory,and specialized for the case of GaAs/AlGaAs quantum well sample. It has been found that is a fairly large quantity as compared with its value in bulk as the well width decreases from values corresponding to the almost bulk situation.