Effects of incident UV light on the surface morphology of MBE grown GaAs

Light-assisted molecular beam epitaxy is a promising technique for improving the growth of metastable semiconductor alloys traditionally grown at low temperatures. The effect of photon irradiation on adatom incorporation dynamics is studied for GaAs homoepitaxy on vicinal surfaces. Irradiation is found to increase the temperature at which the growth mode transitions from layer-by-layer island nucleation to step flow growth and to alter the surface morphology. These surprising changes are discussed in the context of modification of adatom diffusion and incorporation processes. •The observation of a shift in the transition temperature of predominantly step-flow growth in GaAs.•Similar surface morphologies found in illuminated samples as compared to samples grown under dark conditions at 20–30°C cooler.•Identification of two potential mechanisms to explain the observed results.