The growth start on the heterovalent GaAs-ZnSe interface under Te, Se and Zn termination

To improve the properties of ZnSe related devices grown on GaAs substrates or ZnSe/GaAs heterostructures a deeper understanding of the II-VI/III-V interface is necessary. In particular island growth within the first few monolayers will influence the properties of such devices drastically. Because theory predicts an enhanced stability for a special interface layer composition (Kley and Neugebauer, Phys, Rev, B 50 (1993) 8616 [1]), we have varied the starting growth conditions by utilizing Zn, Se or Te termination of the GaAs (100) surface with different coverages. Only the layers grown on Te/GaAs which has a coverage of approximately half a monolayer (ML) Te showed a two dimensional (2D) growth start, pseudomorphic growth up to 400 nm, good crystal quality and reproducible electrical behavior. From all this we can conclude that an initial layer with the theoretically proposed coverage should allow growth to remain in the 2D mode and thus result in an improved crystal quality. Further we have shown that it is possible to double the thickness of pseudomorphic layers compared to values reported by other groups using conventional MBE.