Detailed analysis of radiative transitions from defects in n-type monocrystalline silicon using temperature- and light intensity-dependent spectral Photoluminescence

Sub-bandgap luminescence is characteristic of radiative transitions from defects in semiconductors. However, methods to extract defect-identifying parameters from this luminescence are lacking. Here, we present a method to extract these parameters from temperature- and intensity-dependent micro-photoluminescence (pPL) spectra. The initial coarse analysis determines the relevant radiative recombination mechanism by fitting the integrated defect PL spectra with phenomenological models for the temperature- and intensity-dependence. The subsequent detailed analysis fits the integrated defect PL spectra using rigorous physical models for the defect radiative recombination and spectral line-shape. Finally, defect parameters are extracted, including the defect energy level(s). As we obtain these values directly from the defect luminescence, our method provides higher confidence than more traditional indirect methods, such as those involving band-to-band PL and photoconductance. We demonstrate our method on spatially non-uniform defects with radiative transitions in n-type monocrystalline silicon samples. It is shown that the defect PL originates from the donor-acceptor pair recombination mechanism, involving a shallow acceptor and deeper donor energy level. The acceptor level is extracted from the temperature-dependent spectra, whilst the intensity-dependent spectra give the sum of acceptor and donor energies.