Temperature Dependence of the Band-Edge Injection Electroluminescence of 3C-SiC pn Structure
Abstract
We present the injection electroluminescence spectra in the temperature range 290-760 K of 3C-SiC pn structure, which was fabricated by sublimation epitaxy in vacuum on 6H-SiC substrate. The dominant emission band of injection electroluminescence (IEL) spectrum was observed in the green region; at room temperature the IEL intensity outside the region of hν ≈ 2.0- 2.5 eV was less than 3% of that of the green peak. The peak parameters at room temperature are: hνmax ≈ 2.32 eV, full width at half maximum w ≈ 100 meV. The green peak shifted in the longwave direction with increasing temperature; the hνmax (T) dependence was linear with the slope of - 1.3x10-4 eV/K. Both the IEL intensity of the green peak at hνmax and band width w increased upon heating. The w(T) dependence was linear with the slope of 4.6x10-4 eV/K; intensity increased with the activation energy of 70 meV. The green IEL band can be considered to be due to the free exciton annihilation or to the band-band recombination and edge IEL increasing with rising temperature can be explained by the nonequilibrium charge carriers lifetime increasing.