Spinodal-like decomposition of InGaP epitaxial layers grown on GaP substrates

摘要

The spinodal-like decomposition of InxGa1-xP epitaxial layer prepared by low-pressure metallorganic vapour phase epitaxy was studied by means of photoluminescence and transmission electron microscopy. Epitaxial layers were grown on Gap substrates at T-g = 740 degrees C and reactor pressure of 20 mbar. We show that presence of spinodal-like decomposition occur at, samples with InP mole fraction higher as x = 0.2 and V/III ratio of 75. The low-temperature photoluminescence spectra shows that in partially decomposed samples a characteristic broad band occurred close to 1.985 eV. An increase in the V/III ratio up to a value of 350 suppressed the decomposition, and PL signal with only one narrow transition was obtained. (c) 2005 Elsevier B.V. All rights reserved.