Figure 3. EL and PL spectra of SiC LED recorded at 77 K.

(a) Comparison of the EL (shaded area) and PL spectra under excitation with an energy E_exc = 2.62 eV (473 nm). Inset: The same, but shown in the spectral range where the strongest V_Si ZPL (V1) is expected. (b) PL spectrum obtained under excitation with a He-Ne laser with E_exc = 1.96 eV (633 nm). The V1, V2 and V3 ZPLs characteristic for the V_Si defects in SiC are clearly seen. (c) Integral intensity of the V_Si and D₁ emission bands [the shaded areas in (a)] as a function of LED current. The solid line is a fit (see text for details).