Chemical vapor deposition of zinc chalcogenides using elemental source materials

Abstract

Single crystal layers of ZnS, ZnSe and ZnTe have been grown epitaxially at temperatures between 650 and 940°C on GaAs and GaP substrates in a hydrogen flow system by using metallic zinc as the source material of the group II element and sulfur, selenium or tellurium as the source material of the group VI element. The structural properties of the epitaxial layers are investigated by means of electron diffraction. ZnS layers on the (111)Ga, ( 1 1 1) As and (100) face of GaAs are of the wurtzite, twinned zinc blende and t win-free zinc blende structure, respectively. ZnSe layers on the (111)Ga, ( 1 1 1) As and (100) face of GaAs are of the twinned zinc blende , zinc blende with or without twinning and twin-free zinc blende structure, respectively. ZnTe layers on the (111), ( 1 1 1) and (100) f ace of GaAs and GaP are of the zinc blende structure without twinning. The tendency to twin increases with increasing ionicity of crystal bonding in epitaxial layers, and is higher for epitaxial growth on (111) substrates than on (100) substrates.