Structural and photoluminescence properties of low-temperature GaAs grown on GaAsA substrates

Undoped, uniformly Si-doped, and δ-Si-doped GaAs layers grown by molecular-beam epitaxy on (100)- and (111)A-oriented GaAs substrates at a temperature of 230°C are studied. The [As.sub.4] pressure is varied. The surface roughness of the sample is established by atomic-force microscopy; the crystal quality, by X-ray diffraction measurements; and the energy levels of different defects, by photoluminescence spectroscopy at a temperature of 79 K. It is shown that the crystal structure is more imperfect in the case of GaAs(111)A substrates. The effect of the [As.sub.4] flux during growth on the structure of low-temperature GaAs grown on different types of substrates is shown as well. DOI: 10.1134/S1063782616020081