Layered Growth of Lattice-Mismatched Ga x In1−x P on GaP Substrates by Liquid Phase Epitaxy

Abstract

We report layered growth of Ga x In1−x P on GaP substrates using single-step liquid phase epitaxy (LPE) with a Sn-based melt when the lattice mismatch is greater than 0.4 % (x < 0.95). Compositional control was observed by (1) varying the cooling rate and (2) changing the melt-back temperature at the beginning of the growth. Possible growth mechanisms are proposed to explain the principles of both approaches of compositional control. Smooth epilayers have been observed. High resolution x-ray diffraction was used to characterize the composition of the epilayers, and room temperature photoluminescence was reported for one of the samples with the composition of x = 0.11. Plan-view TEM measurements revealed threading dislocation densities on the order of 108 cm−2 in the upper regions of the Ga x In1−x P epilayers. In contrast, when using In-based melts, LPE of Ga x In1−x P on GaP (100) substrates exhibited island growth at large misfits, whereas edge growth dominated when using GaP (111B) substrates under equivalent growth conditions.