Nitrogen-carbon radiative defect at 0.746 eV in silicon

Nitrogen-doping and -implantation studies reveal a new photoluminescence spectrum in silicon with a no-phonon transition at 0.746 eV. The line exhibits ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ ${,}^{15}$N and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ ${,}^{13}$C isotope splittings showing that single nitrogen and carbon atoms are incorporated in the defect. Zeeman measurements yield trigonal ($C_{3v}$) symmetry of the defect and show that the line is a transition from an isotropic s=(1/2) spin state with $g_{\mathrm{iso}=2\mathrm{}}$ to an anisotropic s=(1/2) spin state with $g_{?}$=3.1 and $g_{\perp }$=1.4 ascribed to a loosely bound electron ($E_e$∼50 meV) and a tightly bound hole ($E_h$∼373.5 meV), respectively.