Effects of thermal annealing on In-induced metastable defects in InGaN films

We investigated the effects of thermal annealing on the properties of InGaN layers. From secondary ion mass spectroscopy results, it was found that severe In desorption occurred after annealing. Photoluminescence and X-ray diffraction results indicate that significant amounts of In vacancy-related defects exist in the annealing samples. It was also found that persistent photoconductivity decay time constants were 211, 893 and 1040 s, while the decay exponents were 0.153, 0.120 and 0.213 for the as-grown, 800 °C-annealed and 1000 °C-annealed InGaN epitaxial layers, respectively.