GaN films were grown by the MBE method on LiGaO2 substrates. Photoluminescence (PL) of the epitaxial films has been studied to characterize the films ex situ. The room-temperature PL spectrum contains an edge PL band and also a broad band of deep-level emission at 2.6 eV. This deep-level emission becomes very small in comparison with the edge emission at helium temperatures. Analysis of the low-temperature data suggests that the films contain both hexagonal and cubic crystallites. The main PL lines at 5.7 K are due to emission of excitons bound on neutral donors in hexagonal and cubic phases of the epitaxial film (3.472 eV and 3.263 eV), D-A pair recombination (3.154 eV) and also free electron-neutral acceptor transition (3.185 eV) in c-GaN. The involved acceptor has a binding energy of about 115 meV.
- GaN films
- gallium nitride