MODEL FOR REFLECTION HIGH-ENERGY ELECTRON-DIFFRACTION INTENSITY RECOVERY DURING GAP GROWTH IN LASER-TRIGGERED CHEMICAL BEAM EPITAXY

Reflection high-energy electron diffraction (RHEED) intensity has been observed while growing GaP by laser-triggered chemical beam epitaxy s imultaneously using a supply of triethylgallium (TEGa) and phosphine ( PH3). The intensity decreases after each laser pulse, and then it reco vers the original value. We present a semiquantitative model in order to explain the RHEED intensity changes. We assume that initially a GaP surface is saturated with chemisorbed diethylgallium (DEGa) and physi sorbed TEGa. Laser irradiation decomposes a fraction of chemisorbed DE Ga, and it reacts slowly with impinging P. TEGa is quickly chemisorbed on the just-reacted GaP and the initial condition is recovered. This model properly fits the experimental data and it allows a deeper under standing of chemical reactions on the surface during chemical beam epi taxial growth of GaP.