STRUCTURAL-PROPERTIES OF ZNSE LAYERS GROWN ON (001)GAAS SUBSTRATES TILTED TOWARD [110]GAAS AND [010]GAAS

We have investigated the structural properties of ZnSe epilayers that were molecular beam epitaxially grown on (001) GaAs substrates with di fferent tilt angles and tilt directions. We measured the properties of the epilayers by x-ray diffraction, transmission electron microscopy, and etch pit density analysis. Tilting the (001) GaAs substrate towar d [010] was very effective in reducing the surface defect density of t he ZnSe layers, while tilting toward the [110] direction was of no use . We could observe the increasingly two-dimensional nature of the init ial growth mode in the (001) GaAs substrate tilted toward [010]. Growt h of a 1.8-mu m-thick ZnSe layer on (001) GaAs tilted 4 degrees toward [010] resulted in a very low surface defect density of 1 x 10(4) cm(- 2). Such a low defect density has seldom been obtained in ZnSe, withou t growing a GaAs buffer layer below the ZnSe layer. (C) 1997 American Institute of Physics.