Surface reaction mechanism in MOVPE growth of ZnSe revealed using radicalsproduced by photolysis of alkyl azide

Epitaxial growth mechanism of ZnSe under alternate supply of diethylzinc (D EZn) and dimethylselenium (DMSe) was studied by in situ optical monitoring of the growing surface. When H-2 was used as carrier gas, the time-dependen t optical reflectance was found to exhibit a sawtooth pattern under DEZn su pply. The sawtooth reflection signal was also observed in growth experiment s using N-2 carrier gas when DEZn was provided after supply of neutral free radicals produced by laser photolysis of alkyl azide. Based on these exper imental results, microscopic mechanism of growth enhancement by coexistent H-2 is discussed in terms of ab initio quantum chemistry. (C) 2000 Elsevier Science B.V. All rights reserved.