A Deep Carbon‐Related Acceptor Identified through Photo‐Induced Electron Paramagnetic Resonance. Issue 4 (22nd December 2019) - Paudel, Subash
Abstract : Herein, a carbon‐related point defect in thick free‐standing carbon‐doped GaN substrates grown by halide chemical vapor deposition is examined. Carbon is intentionally introduced to concentrations between 2 × 10 17 and 10 19 cm −3, and the number of point defects is proportional to the carbon concentration. The carbon center is detected using electron paramagnetic resonance spectroscopy after photo‐excitation with light greater than 2.8 eV. Simultaneous monitoring of the defect and a shallow donor confirms that the excitation occurs via removal of an electron from the deep carbon‐related acceptor and subsequent capture by the shallow donor. The study indicates that the defect level for the carbon defect is at least 0.7 eV above the valence band edge and therefore an excellent candidate for growth of semi‐insulating GaN. Abstract : Herein, the optical response of the carbon‐related acceptor and shallow donor in carbon‐doped GaN using photo‐induced electron paramagnetic resonance spectroscopy is discussed. The work also presents a charge transfer model to describe such photo‐induced behavior. The preliminary result showing a carbon‐related deep‐acceptor with photo‐threshold at least 0.7 eV above the valence band edge is presented.