Band-gap narrowing in heavily doped silicon at 20 and 300 K studied by photoluminescence

The band-gap shrinkage in heavily doped n- and p-type silicon is studied by photoluminescence both at low temperatures (20 K) and at room temperature (300 K). A line-shape analysis was performed to determine the indirect band-gap energy from the emission spectra. Within the experimental accuracy the same band-gap shift is observed at room temperature as at low temperature. The present results are compared with experimental data from other optical studies and with theoretical calculations.