Lateral photovoltaic effect in silicon-based hybrid structures under external magnetic field

Abstract

Charge transport in semiconductor devices is highly sensitive to light, which opens up wide application prospects. The lateral photovoltaic effect (LPE) is widely used in position sensitive detectors due to its high sensitivity to the light spot position. We report on the features of the LPE in silicon-based metal/insulator/semiconductor structures at helium temperatures. To investigate the LPE, Fe/SiO2/p-Si and Mn/SiO2/n-Si structures have been fabricated by molecular beam epitaxy. It has been found by studying the lateral photovoltage that the SiO2/Si interface plays a significant role in transport of photogenerated carriers, mainly via the interface states, which induce electron capture/emission processes at certain temperatures. The value of the photovoltage is likely affected not only by the metallic film thickness, but also by the substrate conductivity type and Schottky barrier. The effect of the magnetic field on the LPE is driven by two mechanisms. The first one is the well-known action of the Lorentz force on photogenerated carriers and the second one is shifting of the interface state energy levels. Basically, the magnetic field suppresses the contribution of the interface states to the LPE, which suggests that the interface-induced transport can be controlled magnetically.