Combined effects of Ga, N, and Al codoping in solution grown 3C-SiC
2010 (English)In: Journal of Applied Physics, ISSN 0021-8979, Vol. 108, no 1, 013503-1-013503-10 p.Article in journal (Refereed) PublishedText
We report on Ga-doped 3C–SiC epitaxial layers grown on on-axis (0001) 6H–SiC substrates using the vapor-liquid-solid technique and different melts. The resulting samples have been investigated using secondary ion mass spectroscopy(SIMS), micro-Raman spectroscopy and, finally, low temperature photoluminescence (LTPL) spectroscopy. From SIMS measurements we find Ga concentrations in the range of , systematically accompanied by high nitrogen content. In good agreement with these findings, the spectra show that the Ga-doped samples are -type, with electron concentrations close to . As expected, the LTPL spectra are dominated by strong N–Ga donor-acceptor pair (DAP) transitions. In one sample, a weak additional N–Al DAP recombination spectrum is also observed, showing the possibility to have accidental codoping with Ga and Al simultaneously. This was confirmed on a non-intentionally doped 3C–SiC (witness) sample on which, apart of the usual N and Al bound exciton lines, a small feature resolved at 2.35 eV comings from neutral Ga bound excitons. Quantitative analyses of the DAP transition energies in the Ga-doped and witness sample gave 346 meV for the optical binding energy of Ga acceptors in 3C–SiC against 251 meV for the Al one. The conditions for the relative observa-tion of Ga and Al related LTPL features are discussed and the demonstration of room temperature luminescence using Ga doping is done.
Place, publisher, year, edition, pages
2010. Vol. 108, no 1, 013503-1-013503-10 p.
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:liu:diva-128847DOI: 10.1063/1.3455999OAI: oai:DiVA.org:liu-128847DiVA: diva2:932652