Luminescence and EPR Characterization of Vanadium Doped Semi-Insulating 4H SiC
In this paper, we report on a photoluminescence (PL) and EPR study of several semiinsulating (SI) 4H SiC samples showing the different compensation regimes due to the presence of V4+ and V3+of different concentration. The samples which contain only V3+ indicates the compensation regime NV≅ND-NA>0 with the Fermi level located in the upper half of the band gap. The presence of V4+ along with V3+ in the other two set of samples indicates the SI behavior of the samples with compensation regime NV>NA-ND>0. Considering that the samples revealed EPR spectrum of vanadium V3+, position of the Fermi level should be also in the upper half of the band gap and mixed conductivity could be expected. UD-3 PL spectrum was observed in vanadium doped SI 4H SiC presented in the samples in V3+/V4+ and V4+/V5+ charge states with compensation regime NV>NA-ND>0. The data obtained prove that the PL and EPR are suitable techniques in determination SI yield in SiC crystal.
Robert P. Devaty, David J. Larkin and Stephen E. Saddow
E. N. Kalabukhova et al., "Luminescence and EPR Characterization of Vanadium Doped Semi-Insulating 4H SiC", Materials Science Forum, Vols. 527-529, pp. 651-654, 2006