Photoluminescence study of C-H and C-D centers in 4H SiC

Eight p-type 4H SiC epitaxial films with p-type doping from 10(15)cm(-3) to 10(17)cm(-3) were implanted with deuterium at room temperature to a fluence of about 10(15) cm(-2). The bound exciton spectrum and the stretch modes of the C-D center are observed for four samples where the p-type doping is below 1.5x10(16) cm(-3) while no deuterium related spectra are seen for the four samples with higher doping levels. We were able to see two harmonic sidebands of the no-phonon lines and their energies are compared with those observed in 6H and 15R SiC. One unusual feature about the photoluminescence spectra of C-H or C-D centers in 4H SiC is the optical quenching effect. One of our deuterium implanted samples showed a strong hydrogen spectrum before implantation. We used this opportunity to compare the quenching effect of both C-H and C-D centers in the same sample.