Hopping polarization photoconductivity of silicon with the involvement of impurity pairs of groups III and V

The long-wavelength bands of absorption by the impurity pairs and photoconductivity in the microwave (8 mm) electric field with the impurity pulse photoexcitation are investigated for Si doped by B, Al, Ga, In, P, As, and Sb in concentrations 10¹⁶–10¹⁸ cm^?3. The correlation between the pair concentration and the emergence of a slow component of photoconductivity relaxation is ascertained. This component is associated with the polarization hopping photoconductivity that emerges due to the optical recharge of impurity states, namely, the ionization of isolated impurities, impurities in pairs, and dipoles (pairs of the majority and compensating impurity ions). The hopping transfer of ion charges during relaxation is analyzed. It is shown that the main contribution to the polarization photoconductivity at relatively low impurity concentrations is made by hopping transitions in impurity pairs; the contribution of hops with the involvement of isolated ions becomes dominant with increasing concentration.