Features of impurity-photoconductivity relaxation in boron-doped silicon

A series of studies of the impurity-photoconductivity relaxation in Si:B is carried out under pulse optical excitation by a narrow-band tunable radiation source in low and “heating” (10–500 V/cm) electric fields. It is shown that the dependence of the carrier-capture time in a band on the applied electric field is nonmonotonic and, in high fields (>75 V/cm), the capture time decreases with increasing field intensity, which is related to initiating the relaxation processes with optical-phonon emission within the band. The dependence of the relaxation rate for the carriers on the excitation-radiation wavelength is investigated, and a decrease in the carrier-capture time in the band is revealed in the vicinity of the Breit-Wigner-Fano resonances caused by direct capture at an impurity with optical-phonon emission.