Splitting of close N-Al donor-acceptor-pair spectra in 3C-SiC

Abstract

Discrete series of lines have been observed for many years in N-Al DAP (Donor Acceptor Pair) spectra in 3C-SiC. Unfortunately, up to now, there has been no quantitative analysis for the splitting of lines in a given shell. This is done in this work for N-Al DAP spectra in 3C-SiC. The samples were non-intentionally doped 3C-SiC layers grown by CVD on a VLS seeding layer grown on a 6H-SiC substrate. From low temperature photoluminescence measurements, strong N-Al DAP emission bands were observed and, on the high energy side of the zero-phonon line, we could resolve a series of discrete lines coming from close pairs. Comparing with literature data, we show that the splitting energy for a given shell is constant and, to explain this shell substructure, we consider the non equivalent sets of sites for a given shell. Results are discussed in terms of the ion-ion interaction containing third and forth multipole terms