Photoluminescence excitation spectra of the free exciton emission in 6H–SiC

We have applied photoluminescence excitation spectroscopy of the free-exciton related emission in 6H–SiC for studying the absorption edge. Detailed comparison with the conventional techniques, absorption measurements and wavelength modulated spectroscopy, is carried out, and our results are compared with those obtained from these techniques. A qualitative model of the absorption mechanism is proposed in order to understand the appearance of peaks in the PLE spectra.