Voltage-Modulated Position Sensitivity and Nonlinearity in a-Si:H/c-Si p-i-n Structure by Different Connection Methods

In this letter, we report a significant finding of the bias voltage-modulated lateral photovoltaic effect in a-Si:H/c-Si p-i-n structure under two different methods. The lateral photovoltaic effect was improved greatly when an external bias voltage was applied, with position sensitivity linearly dependent on the laser power. For method 1, although the position sensitivity is as high as 643.2 mV/mm, the linearity is strongly dependent on the value of bias voltage. However, understanding the nonlinear behavior of method 1, we ingeniously prepared a pair of symmetrical ground electrodes as method 2. It was found that the nonlinearity, which is as good as that without bias voltage, was nearly independent of the value of bias voltage again. Moreover, the largest position sensitivity of 238.1 mV/mm is still much larger than that without bias voltage.