Abstract
We report the results of a series of LTPL (Low Temperature PhotoLuminescence) investigation performed on n-type, non-intentionally doped, 4H-SiC samples. We focus on the defect structure introduced by a growth fault in the stacking sequence. We treat the fault as a 3C quantum well embedded in a 414-SiC matrix and use a simple 2-dimensional approximation to deduce the extent of the lattice perturbation associated with a given defect. We show that the intrinsic type-II nature of the band alignment, combined with the effect of the spontaneous polarization, must result in a double bound-exciton signature per well, which is resolved for the first time. The comparison with experimental results confirms also that, after a relatively small critical layer thickness, the back conversion from cubic to hexagonal remains an unsolved problem. (c) 2005 WILEY-VCH Verlag GmbH W Co.