GROWTH AND CHARACTERIZATION OF HETEROEPITAXIAL CDTE AND ZNTE ON GE(001) BUFFER LAYERS

The microstructure of heteroepitaxial CdTe (001) and ZnTe(001) epilaye rs grown on Ge(001) buffer layers by molecular beam epitaxy has been c haracterized using electron microscopy. Apart from occasional {111} st acking faults originating at the interfacial region, the prevailing de fects present in both systems are identified by high-resolution imagin g as perfect Lomer edge dislocations with Burgers vectors of the type a/2[110] parallel to the interface plane, which are indicative of well -relaxed material. Double-crystal rocking-curve measurements using Ge( 001) buffer layers give full-width-at-half-maximum values of 210 are-s ec for a 7.5 mu m thick ZnTe film and 125 are-sec for a 12 mu m thick CdTe film. Use of the Ge buffer layers on Si(001) substrates represent s a valuable precursor for eventual growth of mercury cadmium tellurid e since this allows the substrate orientation to be maintained. The bu ffer layer also permits a substantial reduction of the in situ anneali ng temperature needed for substrate oxide removal. (C) 1996 American I nstitute of Physics.