Magneto-optical studies of free-standing hydride-vapor-phase epitaxial GaN

Magneto-optical studies of donor excitation in hydride-vapor-phase epitaxial GaN are reported. Donor ground-to-excited state transitions are observed in the infrared for Si, O, and a third unidentified donor as a function of magnetic field to 11 T. Transitions from the ground state to 2p_± and 3p_± excited states are studied. Values for effective mass ground and excited state binding energies are determined from the observed excited-state separation. We find a value of 29.1±0.5meV for the effective-mass donor binding energy in GaN. Ground state binding energies for SiGa and ON are 30.18±0.1meV and 33.20±0.1meV, respectively. Separation rates for the 2p₊ and 2p_- excited states with magnetic field are consistent with an electron effective mass of 0.22m₀.