2Instituto de Investigación en Comunicación Optica, Universidad Autónoma de San Luis Potosí, Alvaro Obregón #64, San Luis Potosí, 78000, México.

The heteroepitaxy of ZnSe on GaAs presents problems like the 0.2% lattice mismatch and the interdiffusion of the elements of the substrate into the epitaxial layer. In order to overcome these problems we grew ZnSe films on GaAs substrates with In_xGa_1-xAs and Al_xGa_1-xAs buffer layers. The III-V buffer layers were grown by molecular beam epitaxy (MBE) with a thickness of 500 nm, and capped with a protective As layer. Then, the substrates were transferred in air to the II-VI MBE system. The As capping layer was desorbed prior to the ZnSe growths. ZnSe films of different thickness were grown at a substrate temperature of 320 ° C, using a beam equivalent pressure ratio of Se/Zn=3. Differential photoreflectance, photoluminescence spectroscopy, transmission electron microscopy, and atomic force microscopy were employed to study the optical and structural properties of the epitaxial layers. The results showed that the best quality ZnSe films were obtained on In_xGa_1-xAs buffer layers with an In concentration of x = 0.1, and those grown on Al_xGa_1-xAs buffer layers with an Al concentration of x = 0.01.

This work was partially supported by CONACyT.