Free to bound transition-related electroluminescence in 3C and 6H SiC p+–n junctions at room temperature

Abstract
The room temperature electroluminescence spectra of moderately nitrogen doped (1×1017 cm−3) 3C and 6H SiC p+n junctions are studied as a function of forward current. The free to bound transition due to the unintentional, deep boron (defect) center is dominant at low forward bias, while the free to bound transitions due to nitrogen donors and aluminum acceptors are dominant at higher forward biases. These results can be explained using Shockley–Read–Hall analysis of the recombination rate as a function of bias. The origin of boron related electroluminescence is suggested to be primarily from recombination within the depletion region, while aluminum and nitrogen related electroluminescence is attributed to recombinations in the minority carrier injection regions.