Charge transfer process for carbon-related center in semi-insulating carbon-doped GaN

Academic Article


  • Electron paramagnetic resonance (EPR) spectroscopy was used to study the point defects in 2 × 1017-1019 cm−3 C-doped GaN substrates grown by hydride vapor phase epitaxy. The intensity of an isotropic signal with g = 1.987 ± 0.001 increased monotonically with the carbon concentration, indicating that the EPR signal represents a carbon-related defect. In each sample, the signal intensity increased under illumination with photon energy greater than 2.75 eV, and the photo-induced signal decreased with subsequent illumination at 0.95 eV. A second signal, well-documented to be a shallow donor, appeared along with the g = 1.987 signal in the most lightly doped samples. The appearance of the donor confirms that the photo-induced increase is caused by excitation of an electron to the conduction band and implies that a defect level for the carbon-related center is about 1 eV above the valence band edge, consistent with temperature-dependent Hall measurements.
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    Author List

  • Zvanut ME; Paudel S; Sunay UR; Willoughby WR; Iwinska M; Sochacki T; Bockowski M
  • Volume

  • 124
  • Issue

  • 7