In this paper, we report on a study of the spinodal-like decomposition of InxGa1-xP grown on (100) Gap substrates at 740 degrees C by metalorganic vapor phase epitaxy (MOVPE). We concentrated our efforts on an alloy with the InP mole fraction close to x = 0.27, at which the indirect-to-direct band-gap structure crossover occurs. We used the V/III ratio and growth rate for the limitation of diffusion length of adatoms before their incorporation into an epitaxial layer. Transmission electron microscopy (TEM) together with energy dispersive X-ray analysis (EDX) and low-temperature photoluminescence were used to demonstrate that a spinodal-like decomposition of such InGaP layers can partially be suppressed if the V/III ratio is increased from a starting value of 75-350. Next improvement in the quality of the epitaxial layer may be achieved by an increase of the growth rate v(g) up to value higher as 1.1 mu m/h. (c) 2006 Elsevier B.V. All rights reserved.