Zeeman spectroscopy of shallow donors in GaN

Gallium nitride grown by hydride vapor phase epitaxy has been studied by infrared spectroscopy in the region of donor intrasite electronic excitations as a function of magnetic field and temperature. Infrared-absorption features which are present only when the sample temperature is cooled to near 4 K have been observed. These features are identified as due to 1s-2p_± transitions which split in a magnetic field, and a 1s-2p₀ transition which does not split. A donor effective mass of 0.22m₀ is calculated from the rate of splitting with field. We assume that the lower-energy transition occurs at an effective-mass donor and calculate donor binding energies of 31.1 and 33.8 meV for the two donors observed, and a static dielectric constant of 9.8.