Impurity investigation and structural quality determination of GaAs epilayers from mixed solvents (Ga+Bi)

Abstract

GaAs epilayers grown from 100% Ga, 100% Bi and mixed solvents were investigated by low-temperature photoluminescence (PL) and Auger electron spectroscopy (AES). The change in the photoluminescence spectra was analyzed as a function of the bismuth content in the solution. From the AES, the carbon (C) concentration in 50% Bi-grown layers is less when compared to other Bi-grown layer and Ga-grown layer. There is no Bi related peak in the GaAs epilayers which is grown using Bi mixed solvents. The structural quality of the epilayer due to the variation of Bi in Ga solvent was revealed by molten KOH. The etch pit density (EPD) reduced to more than half the order of magnitude for the epilayer grown from the Bi solvent when compared to Ga-grown epilayer. The carrier lifetime was determined by the time-resolved photoluminescence (TRP). Epilayer from Bi 50% solvent has longer minority carrier lifetime.