The interdiffusion of In and Ga was observed in multiple quantum-wells during annealing at temperatures of 1300 to 1400C. Hydrostatic pressures of up to 15kbar were applied in order to prevent surface decomposition. The In-Ga interdiffusion coefficient was estimated to be 8 x 10-18cm2/s. In as-grown material, the X-ray diffraction spectra exhibited InGaN diffraction peaks of up to fourth order. After annealing at 1400C for 0.25h, only the zero-order peak was observed; as a result of compositional disordering of the quantum-well superlattice. Transmission electron microscopy confirmed that the superlattice was completely disordered after annealing at 1400C for 0.25h.

Interdiffusion of In and Ga in InGaN Quantum Wells. M.D.McCluskey, L.T.Romano, B.S.Krusor, N.M.Johnson, T.Suski, J.Jun: Applied Physics Letters, 1998, 73[9], 1281-3