砷化镓异质外延薄膜的近红外光致发光研究

Studies on the Near Infrared Photoluminescence of Heteroepitaxial GaAs

本文通过在硅衬底上用ＭＯＣＶＤ方法生长的砷化镓外延薄膜的变激发强度的近红外光致发光，研究了在液氮温度下峰值为１．１３与１．０４ｅＶ两个发光带的发光特性。这两个发光带的峰值随激发强度的变化特性表明，这两个发光带均属施主－受主对复合发光。由于发光带中存在着强的电子－声子耦合，所以应在施主－受主对复合发光的能量表示式中计及Ｆｒａｎｃｋ－Ｃｏｎｄｏｎ位移能，从而获得了施主－受主对复合发光的新的能量表示式。通过对复合发光带峰能随激光强度变化的实验与理论表达式的拟合，确定了峰值为１ｌ．１３与１．０４ｅＶ这两个发光带的施主－受主对的能级结构。

This paper presents the result of the studies on the near infraredphotoluminescence characteristics of the two emission bands with peak energies 1. 13 and1.04 eV,emitted by the GaAs epilayers grown by MOCVD on Si substrates under variousexcitation intensities at nitrogen-liquid temperature. It shows that these two emissionbands belong to the photoluminescence of donor-accepter pair recombination. The experimental results show that the Franck-Condon shift should be taken into account becauseof the strong electron-phonon coupling, and a new expression for the energy ofrecombination of donor-acceptor pairs has been obtained. Finally, the structures of the energy levels of these two donor-acceptor pairs with peak energies 1.13 and 1.04 eV havebeen determined respectively in terms of the simulations between the experimental curvesand the theoretical expressions.