Study of donor–acceptor pair luminescence in highly doped and compensated Cz silicon
The photoluminescence (PL) of highly doped and compensated Czochralski silicon has been investigated. The low-temperature PL spectra show a donor-to-acceptor zero-phonon broad band and clearly distinguished phonon replica shifting to the blue side with increasing the net doping concentration in silicon crystal. The data are consistent with DAP luminescence involving an acceptor level of about 46 meV above the valence band edge in silicon. The analysis of temperature evolution of the PL spectra indicate that the observed PL spectra are due to a donor–acceptor pair recombination with a donor level located at 46 meV. The redshift of this band with increasing excitation power was also observed. The dependence of the emission peak energy on the excitation power is characteristic of highly compensated material in which potential fluctuations influence the band structure.