4H-SiC band structure investigated by surface photovoltage spectroscopy

The conduction and valence band structure of high-purity 4H-SiC epilayers have been studied by surface photovoltage spectroscopy (SPS). A comparison between defect-free and single-layer stacking fault affected areas is reported. Electronic transitions, determined by SPS, are in good agreement with ab initio calculations. Electronic transitions and changes in band occupation have been observed in stacking fault rich areas below the band gap. Moreover, stacking faults induce the presence of a split-off band below the conduction band and a modification of the electron density of states in the conduction band always at the M point.