Electric-field-induced new features in the photoconductivity of extrinsic silicon

Abstract
Under low background radiation and at low temperatures (∼1.4 K) the extrinsic photoresponse of phosphorus- and antimony-doped silicon exhibits a peak below the ionization energy of the impurity, when an electric field is applied. This peak grows in intensity and shifts (up to 2 meV) to lower energies as the electric field is increased. Both the position and the intensity of the peak saturate at a critical field which depends inversely on the impurity concentration. A possible explanation of the observed features is proposed.