Low pressure OMVPE of ZnSe with hydrogen selenide and dimethylzinc-triethylamine

Abstract

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 dimethylzincrtriethylamine (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°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 photo-luminescence 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.