Reactive sticking of As4 during molecular beam homoepitaxy of GaAs, AlAs, and InAs

Abstract

We have measured transient and steady-state reflected As4 and desorbing As2 fluxes during molecular beam homoepitaxy on the (001) surfaces of GaAs, AlAs, and InAs. In the absence of growth, the reflected As4 flux decreases, and the desorbing As2 flux increases, with increasing temperature. In the presence of growth, both fluxes decrease linearly, and then saturate, with increasing group III flux. The saturated reflected As4 flux depends on temperature, and ranges from approximately 1/2 at temperatures commonly associated with high-quality epitaxy, to zero at lower temperatures; the saturated desorbing As2 flux is zero, independent of temperature. The reflected As4 (but not the desorbing As2 ) flux also depends on surface reconstruction, resulting in unexpected transients as surfaces sequence through various reconstructions upon initiation of growth.