Temperature activated 1.2 eV photoluminescence in semi-insulating SiC wafers

摘要

Temperature dependent photoluminescence (PL) spectroscopy was performed on semi-insulating and self-compensated (non-vanadium doped) 6H-SiC wafers. PL intensity of the infrared band at 1.2 eV shows a remarkable increase up to two orders of magnitude, when the temperature was raised from 110 K to 175 K. We correlate the temperature dependence of the 1.2 eV PL band with dark and photoconductivity variation in the temperature range from 77 K to 300 K. Concurrently, thermally stimulated luminescence and thermally stimulated conductivity studies have been performed to provide information on the electron-hole traps participating in radiative transitions. A recombination model of the 1.2 eV band transition is proposed.