| Autor: |
Sun, J. W., Zoulis, G., Lorenzzi, J. C., Jegenyes, N., Peyre, H., Juillaguet, S., Souliere, V., Milesi, F., Ferro, G., Camassel, J. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; Jul2010, Vol. 108 Issue 1, p013503, 10p, 2 Charts, 7 Graphs |
| Abstrakt: |
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 Si1-xGax melts. The resulting samples have been investigated using secondary ion mass spectroscopy (SIMS), micro-Raman spectroscopy (μ-R) and, finally, low temperature photoluminescence (LTPL) spectroscopy. From SIMS measurements we find Ga concentrations in the range of 1018 cm-3, systematically accompanied by high nitrogen content. In good agreement with these findings, the μ-R spectra show that the Ga-doped samples are n-type, with electron concentrations close to 2×1018 cm-3. 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. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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