Silicon vacancy annealing andDIluminescence in6H−SiC

Abstract

Combining electron paramagnetic resonance measurements with ab initio calculations, we identify the $V_{\mathrm{C}}{\mathrm{C}}_{\mathrm{Si}}\left({\mathrm{Si}}_{\mathrm{C}}{\mathrm{C}}_{\mathrm{Si}}\right)$ complex as a second annealing product of the silicon vacancy via an analysis of resolved carbon hyperfine interactions and of the zero-field splitting parameter of its excited triplet state. At high temperatures the carbon vacancy can dissociate from this complex leaving behind a diamagnetic ${\mathrm{Si}}_{\mathrm{C}}{\left({\mathrm{C}}_{\mathrm{Si}}\right)}_2$ complex, which is proposed to be an excellent candidate to cause the $D_{\mathrm{I}}$ photoluminescence spectrum: the calculated local vibration modes fit very well with the characteristic phonon assisted structure of the photoluminescence-spectra. Furthermore, our model provides a detailed explanation for the excitonic electron-hole recombination responsible for the $D_{\mathrm{I}}$ luminescence.