Two-dimensional lateral photovoltaic effect in MOS structure of Ti–SiO₂–Si

Abstract

Previous works on lateral photovoltaic effect (LPE) were mostly limited to one dimension, but this paper explored two-dimensional characteristics of metal-oxide-semiconductor (MOS) sensor by preparing Ti-SiO 2 -Si samples with high sensitivity. The experiment shows that the lateral photovoltage (LPV) sensitivity decreases gradually when the laser scanning direction deviates from the line between two electrodes. However, there is nonlinear between the LPV and laser point position but it has symmetry when the scanning direction is perpendicular to the line between the two electrodes. Meanwhile, the mechanism of LPE is explained by carrier diffusion theory, further experiments and calculation of difference between laser point position and the two electrodes, the results prove that the difference and LPV are the same variation trend with the laser point position. Based on this phenomenon, the mathematical equation between the difference and LPV is clarified, this can be a new choice for two-dimensional displacement detection of MOS sensor.