Observation of ordering and phase separation in InxGa1-xN layers

A series of InGaN layers grown by metalorganic vapour deposition and molecu lar beam epitaxy have been investigated by transmission electron microscopy (TEM). It is shown that for In concentrations lower than 15%, the InGaN la yers has a crystalline quality comparable to that of the underlying thick G aN buffer layer. Both ordering inside the InGaN Alms and phase separation h ave been observed when the In concentration was brought over 20%; they are found to depend on the growth conditions as well. (C) 1999 Elsevier Science S.A. All rights reserved.