The photoluminescence (PL) technique at liquid helium tempera-ture has been applied to characterization of shallow imparities and thermal defects in silicon crystals. A number of PL spectra of B-doped and P-doped Sj with different doping levels have been obtained together with quantitative analysis. A concentration of boron as low as 5×1011 cm-3 in highly pure Si could be detected. The dependence of PL intensity on excitation intensity was investigated. We have also applied the PL technique in the analysis ...