Role of Fermi-level depinning in quenching of V⁴⁺ related photoluminescence in semi-insulating 4H-SiC

Abstract

Vanadium atoms in 4H-SiC single crystals have prospective applications as solid-state quantum emitters, making it crucial to understand the modifications of vanadium-related optical properties due to defects in the host lattice. We introduce controlled defects using 100 MeV Ag ion irradiation and report on the quenching of luminescence from the neutral vanadium V4+ atoms in vanadium-doped semi-insulating 4H-SiC. A reduction in intensity from V4+ related α and β emissions, and a correlated increase in the thermally stimulated current (TSC), attributed to the increase in irradiation-induced defects, are observed with increasing ion fluence (Ag/cm2). The activation energies of the defect levels involved in the compensation loss are estimated from TSC. We also demonstrate a partial recovery of the semi-insulating behavior after thermal annealing.