Determination of Bulk Lifetime and Surface Recombination Velocity of Silicon Ingots From Dynamic Photoluminescence

This paper elaborates upon the theory of self-consistent minority carrier bulk lifetime measurements of silicon ingots via time-modulated photoluminescence and presents an experimental proof of concept. For silicon ingots, the solution of the continuity equation at harmonic time modulation of excess carrier generation is shown to generally reveal a remarkably pronounced contrast with respect to minority carrier bulk lifetime. We combine our dynamic self-consistent approach with an analysis of surface recombination velocity from photoluminescence intensity ratios upon irradiation with different laser wavelengths. This combined analysis enables an accurate simultaneous determination of bulk lifetime and surface recombination velocity. For sufficiently high or accurately known ingot surface recombination velocities, this approach could likewise be used for an accurate determination of the minority carrier diffusion coefficient and of minority carrier mobility in novel silicon materials.