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 ${2p}_{\pm }$ and ${3p}_{\pm }$ 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 $29.1\pm 0.5\mathrm{meV}$ for the effective-mass donor binding energy in GaN. Ground state binding energies for ${\mathrm{Si}}_{\mathrm{Ga}}$ and ${\mathrm{O}}_{\mathrm{N}}$ are $30.18\pm 0.1\mathrm{meV}$ and $33.20\pm 0.1\mathrm{meV},$ respectively. Separation rates for the ${2p}_{+}$ and ${2p}_{-}$ excited states with magnetic field are consistent with an electron effective mass of ${0.22m}_0.$