In situ luminescence measurement of 6H-SiC at low temperature

To understand the evolution of defects in SiC during irradiation and the influence of temperature, in situ luminescence measurements of 6H-SiC crystal samples were carried out by ion beam induced luminescence (IBIL) measurement under 2 MeV H⁺ at 100 K, 150 K, 200 K, 250 K, and 300 K. A wide band (400-1000 nm) was found in the spectra at all temperatures, and the intensity of the IBIL spectra was highest at 150 K among the five temperatures. A small peak from 400 nm to 500 nm was only observed at 100 K, related with the D1 defect as a donor-acceptor pair (D-A) recombination. For further understanding the luminescent centers and their evolution, the orange band (1.79 eV) and the green band (2.14 eV) in the energy spectrum were analyzed by Gaussian decomposition, maybe due to the donor-deep defect/conduction band-deep defect transitions and Ti related bound excition, respectively. Finally, a single exponential fit showed that when the temperature exceeded 150 K, the two luminescence centers' resistance to radiation was reduced.