Interdiffusion of In and Ga in InGaN quantum wells

Interdiffusion of In and Ga is observed in InGaN/GaN multiple quantum wells for annealing temperatures of 1300–1400 °C. Hydrostatic pressures of up to 15 kbar were applied to prevent surface decomposition. In as-grown material, x-ray diffraction spectra show InGaN diffraction peaks up to the fourth order. After annealing at 1400 °C for 15 min, only the zero-order peak is observed, as a result of compositional disordering of the quantum well superlattice. Transmission electron microscopy confirms that the superlattice is completely disordered after annealing at 1400 °C for 15 min.