In this paper, we present experimental results of photoluminescence for series of InAs:Si heavily doped samples, with doping level varying from 1.6 × 1016 cm-3 to 2.93 × 1018 cm-3. All samples were grown using MBE system equipped with a valved arsenic cracker. The measurements were performed in the temperature range of 20 K to 100 K. Although the Mott transition in InAs appears for electron concentrations above 1014 cm-3, Burstein-Moss broadening of photoluminescence spectra presented in this article was observed only for samples with concentration higher than 2 × 1017 cm-3. For the samples with lower concentrations two peaks were observed, arising from the band gap and defect states. The intensity of the defect peak was found to be decreasing with increasing temperature as well as increasing concentration, up to the point of disappearance when the Burstein-Moss broadening was visible.