Large Near-Infrared Lateral Photovoltaic Effect of ITO/Si Structure Observed at Low Temperature

In this paper, the power- and wavelength-dependent lateral photovoltaic effect (LPE) in an indium tin oxide/Si structure is first studied at different temperatures ranging from 292 to 80 K. It was found that the position sensitivity increased gradually until it became saturated with increasing laser power at a constant temperature, and the saturated position sensitivity increased nearly linearly from 2.47 to 3.91 mV/mm with increasing wavelength from 405 to 980 nm at 292 K. More importantly, the position sensitivity also increased considerably with decreasing temperature from 292 to 80 K, and the position sensitivity of 7.47 mV/mm at 80 K is about 1.91 times as large as that of 292 K under illumination of 70 mW for 980-nm laser. Based on the temperature-dependent Schottky barrier height, these results can be well explained. The significant observation of the improved LPE in infrared region makes this structure great potential in infrared position sensitive detectors, especially at low temperature.