Materials Science Forum, Vol.433-4, 309-312, 2002
Photoluminescence up-conversion processes in SiC
Efficient photoluminescence up-conversion is observed in 4H SiC samples containing both the UD-3 defect with its characteristic photoluminescence (PL) no-phonon (NP) line in the near infrared at 1.356 eV and the titanium impurity with its emission in the visible spectral region. When both defects are present, the titanium emission can be excited efficiently by tuning the laser to UD-3. In 4H samples containing either only UD-3 or only titanium, a different photoluminescence up-conversion process can be observed. This second process occurs at photon energies higher than approximately 1.5 eV without exhibiting a clear threshold. In 6H and 15R SiC only this second process was found, even when both the UD-3 defect and the titanium impurity are abundant.