Point defects of ZnSe epilayers grown by hot wall epitaxy

Abstract

The ZnSe epilayers were grown on the GaAs substrate by hot wall epitaxy. After the ZnSe epilayers were treated in the vacuum, Zn- and Se-atmosphere, respectively, the defects of the epilayer were investigated by means of low-temperature photoluminescence measurement. The dominant peaks at 2.7988 and 2.7937 eV obtained from the PL spectrum of the as-grown ZnSe epilayer were found to be consistent with the upper and the lower polariton peak of the exciton. I 2 (D°, X), bounded to the neutral donor associated with the Se-vacancy. This donor-impurity binding energy was calculated to be 25.3 meV. The exciton peak, I 1 d, at 2.7812 eV was confirmed to be bound to the neutral acceptor which corresponded with the Zn-vacancy. The I 1 d peak was dominantly observed in the ZnSe/GaAs:Se epilayer treated in the Se-atmosphere. This Se-atmosphere treatment may convert the ZnSe/GaAs:Se epilayer into the p-type. The SA peak was found to be related to a complex donor like a (V Se–V Zn)–V Zn.