The thermal stability of multiple quantum-wells, with InN mole fractions of 0.23 to 0.30, was investigated by means of post-growth thermal annealing. Low-temperature photoluminescence spectroscopy was used to determine the temperature dependence of the interdiffusion of In and Ga. The interdiffusion could be characterized by a single activation energy of about 3.4eV (figure 6), and was thought to be governed by vacancy-controlled second-nearest neighbour hopping. Due to compositional inhomogeneity, a lower diffusivity was observed in the early stages of thermal annealing.

Interdiffusion of In and Ga in InGaN/GaN Multiple Quantum Wells. C.C.Chuo, C.M.Lee, J.I.Chyi: Applied Physics Letters, 2001, 78[3], 314-6

Figure 6

Interdiffusion in InGaN/GaN Multiple Quantum Wells