Interaction of low-temperature surfactant-grown InAs superlattice layers with arsenic precipitates

Abstract

Double crystal X-ray diffraction (DCXRD), transmission electron microscopy (TEM) and photoluminescence (PL) measurements were used to study the effect of post-growth annealing temperature on the structural properties of novel low growth (250 °C) and normal growth (450 °C) temperature InAs surfactant-mediated grown materials. Under conditions of “arsenic-free” growth, high-quality InAs–GaAs superlattices are obtained at low temperatures (LT) even at thicknesses as high as 3 monolayers (MLs) for InAs. The interaction of the built-in strain fields and the point defects in LT-GaAs both before and after annealing has been studied in detail. DCXRD studies show that the thickness of the LT-grown InAs layers decreased by up to 0.7 ML as the annealing temperature increased to 550 °C. There is evidence from the DCXRD and TEM that the LT InAs–GaAs superlattice structure starts to distort at annealing temperatures above 450 °C. In comparison, the sample grown at normal temperature, 450 °C, still retained the periodicity of the superlattice layers up to an annealing temperature of 650 °C without any change in the thickness of either the InAs (wetting layer) or GaAs.