Photoluminescence spectra of undoped GaAs grown by molecular-beam epitaxy at very high and low substrate temperatures

Abstract

The incorporation mechanisms of residual impurities in GaAs layers grown by molecular-beam epitaxy has been investigated by high-resolution photoluminescence (PL) spectroscopy at 2 K. A systematic study of near-band-edge emissions of undoped GaAs layers grown at a wide range of growth temperatures (Tg), 470-750 °C, demonstrates that PL spectra related with residual impurities are significantly dependent upon Tg. It was found that maximum emission intensity of free exciton is obtained at Tg ∼550 °C, and the minimum impurity incorporation is established at T g of 550-650 °C.