Compositional inhomogeneity in a GaInN ternary alloy layer is investig
ated. A theoretical estimation of the interaction parameter based on t
he delta lattice parameter suggests that the immiscibility of InN in a
nitride alloy is very strong. We investigate the compositional splitt
ing and the existence of InN inclusion in the GaInN epilayer grown on
sapphire (0001) substrates. Thc mechanism of compositional inhomogenei
ty is discussed. (C) 1997 American Institute of Physics.