Metalorganic Molecular Beam Epitaxial Growth of ZnSe and ZnS on GaAs Substrates Pretreated with (NH4)2Sx Solution

We tried to prepare ZnSe and ZnS epilayers on GaAs(100) substrates pretreated with a (NH4)2S x solution. As a result, it was found that it is possible to grow ZnSe with layer-by-layer or two-dimensional growth from an initial stage of growth under appropriate growth conditions. The surface morphologies of ZnSe and ZnS epilayers are better than those grown on GaAs substrates pretreated in a conventional manner in which GaAs is heated to remove the surface oxidized layer. Furthermore, it was also found that the optical properties of thin ZnSe and ZnS epilayers can greatly be improved through pretreatment of the substrates with (NH4)2S x solution.