Levine, I.; Gamov, I.; Rusu, M.; Irmscher, K.; Merschjann, C.; Richter, E.; Weyers, M.; Dittrich, T.: Bulk photovoltaic effect in carbon-doped gallium nitride revealed by anomalous surface photovoltage spectroscopy. Physical Review B 101 (2020), p. 245205/1-7
10.1103/PhysRevB.101.245205
Abstract:
A bulk photovoltaic effect was observed in insulating carbon-doped gallium nitride crystals by investigating the light-induced change of the contact potential difference with a Kelvin probe as a function of the carbon concentration in the crystal. Bulk polarization was caused by excitation of defects setting in at photon energies of 0.95–1.05 eV (C1) and 2.5–2.6 eV (C3). From the dependence on the carbon concentration, C1 can be assigned to isolated carbon defects and C3 to tricarbon defects.