chemical vapor deposition on (1 1 ̄ 0 2) r-plane sapphire substrates. Optical properties of
the films were studied by photoluminescence spectroscopy. Our experimental results
suggest that not VGa but the VGa–ON complex is the key defect responsible for yellow
luminescence in GaN. At 12.9 K, free exciton A, donor bound exciton and exciton bound to
neutral acceptor (Ix), which are similar to (0001) GaN are observed. Different to (0001) GaN …