Zeeman spectroscopy of shallow donors in GaN

Abstract

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 ${1s\ensuremath{-}2p}_{\ifmmode\pm\else\textpm\fi{}}$ transitions which split in a magnetic field, and a ${1s\ensuremath{-}2p}_{0}$ transition which does not split. A donor effective mass of ${0.22m}_{0}$ 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.