Photoluminescence study of Si-doped (1120) a-plane GaN grown on (1102) r-plane sapphire by metalorganic chemical vapor deposition

摘要

Reasonable quality Si-doped (1120) a-plane GaN have been grown by metalorganic chemical vapor deposition on (1102) r-plane sapphire substrates. Optical properties of the films were studied by photoluminescence spectroscopy. Our experimental results suggest that not V_(Ga) but the V_(Ga)-O_N 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 (I-x), which are similar to (0001) GaN are observed. Different to (0001) GaN, the longitudinal optical and transverse optical phonon replicas are found emerging simultaneously. Another peak at 3.42eV is interpreted as donor-acceptor pair transition.