Impurity and defect centers of n-type 4H-SiC single crystals investigated by a photoluminescence and a piezoelectric photo thermal spectroscopy

The deep defect level in n-type 4H-SiC single crystal were investigated from the two physical viewpoints of non-radiative and radiative recombination by using PPT and PL techniques, respectively. Three peaks appear at 2.10, 2.35 and 2.80 eV in the PL spectra and two broad peaks appear around 2.2 and 2.7 eV in the PPT spectra. These were explained by the electron transition through impurity and a defect levels with a phonon relaxation process in terms of the CC model. The strong electron-lattice interaction in the electron transition is understood by those two high sensitivity techniques.