Thermal Annealing Of Cubic-Ingan/Gan Double Heterostructures

We have performed annealing experiments with c-InGaN/GaN double heterostructures in order to obtain information on the thermal stability and the formation process of In-rich clusters in the InGaN layers. While the as grown samples showed a dominating luminescence at about 2.3 eV, the annealed samples showed a new luminescence peak at 2.8-3.0 eV which may be due to a band gap emission of a regenerated layer with an In-content of about x = 0.20. These results are corroborated by micro Raman spectroscopy. Our annealing experiments show that at elevated temperatures In-atoms can diffuse in c-InGaN layers while In-rich aggregates are stable at growth temperature.