On the composition of luminescence spectra from heavily doped p-type silicon under low and high excitation

Abstract

We present a systematic investigation of the effects of doping on the luminescence spectra from p-type crystalline silicon wafers. First, we explain the difference in the approaches between the line shape analysis and the generalized Planck’s law in modeling the spectral shape, and connect the two methods together. After that, we elucidate the separate impacts of individual phenomena including band gap narrowing, band tails and dopant bands, Fermi level shifting, and hot carriers on the luminescence spectra in heavily-doped silicon. Finally, employing appropriate excitation levels, we can unambiguously re-examine the growing of the band tails and the broadening of the shallow dopant band, as well as the merging of the valence and shallow dopant bands together, on measured luminescence spectra.