Effect of low-temperature interphase charge transport at the Si/SiO2 interface on the photoresponse of silicon barrier structures

The effect of low-temperature electron charge redistribution at the Si/SiO₂ interface between the interphase states and the conduction band of an n-Si crystal on the temperature behavior of conductance, photovoltage, and photocurrent in Si barrier structures with edge surface electron channels was studied in the temperature range of 77–300 K. The dynamics of the channel-current response to the voltage changes in the dark and under illumination can be explained qualitatively by dispersive hopping transport of holes in SiO₂, which induces electron transfer to, and accumulation at, the Si surface near the barrier contact. The leveling off of the photovoltage at low temperatures and the nonmonotonic temperature dependence of the photocurrent are attributed to the nonmonotonically increasing, localized hole density at the Si/SiO₂ interface and the free electron density at the Si surface with decreasing temperature, which reflects changes in the valence of oxygen complexes.