Layered Growth of Lattice-Mismatched GaxIn1 xP on GaP Substrates by Liquid Phase Epitaxy

We report layered growth of GaxIn1 xP 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. Planview TEM measurements revealed threading dislocation densities on the order of 10 cm 2 in the upper regions of the GaxIn1 xP epilayers. In contrast, when using In-based melts, LPE of GaxIn1 xP on GaP (100) substrates exhibited island growth at large misfits, whereas edge growth dominated when using GaP (111B) substrates under equivalent growth conditions.