Charge transfer process for carbon-related center in semi-insulating carbon-doped GaN
Abstract
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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 21, 2018
- Source ID
- 10.1063/1.5037598
Entities
People
- M. E. Zvanut
- Małgorzata Iwińska
- Michal Boćkowski
- Subash Paudel
- Tomasz Sochacki
- U. R. Sunay
- W. R. Willoughby
Organizations
- Division of Materials Research
- Office of Naval Research
- Polish Academy of Sciences
- University of Alabama at Birmingham