LOW-PRESSURE OMVPE OF ZNSE WITH HYDROGEN SELENIDE AND DIMETHYLZINC-TRIETHYLAMINE

The growth and nitrogen doping of ZnSe by low pressure organometallic vapor phase epitaxy (OMVPE) have been investigated in a vertical downflow reactor equipped with a laser interferometer for in-situ growth rate measurements, and a microwave plasma cavity for precracking of ammonia for nitrogen doping. Particular emphasis is placed on understanding growth characteristics obtained with H2Se and the new adduct source dimethylzinc:triethylamine (DMZn:NEt3), as compared to those obtained with H2Se and DMZn. At higher temperatures and pressures, growth results obtained with DMZn:NEt3 are similar to those obtained using DMZn with the morphology exhibiting familiar hillock-shaped features. At lower temperatures (<300-degrees-C) and pressures (<30 Torr), growth rates are higher with the adduct source and the surface morphology is improved relative to films synthesized with DMZn. Hall measurements and photoluminescence spectra of the grown films demonstrate that DMZn and DMZn:NEt3 produce material with comparable electronic and optical properties. Microwave plasma decomposition of ammonia is investigated as a possible approach to increasing nitrogen incorporation in ZnSe and photoluminescence spectra are compared to those realized with conventional ammonia doping.