Triple Shockley type stacking faults in 4H-SiC epilayers

4H-SiC epilayers have been characterized by microphotoluminescence (micro-PL) spectroscopy and micro-PL intensity mapping at room temperature. A type of stacking fault (SF) with a peak emission wavelength at 480 nm (2.58 eV) has been identified. The shape of this SF is triangular revealed by the micro-PL intensity mapping. Conventional and high-resolution transmission electron microscopies have been carried out to investigate the structure of this SF. Its stacking sequence is determined as (3,5) in Zhdanov's notation, which is consistent with that of the triple Shockley SF. The formation mechanism of this SF is also discussed.