Self-powered ZrO2 nanofibers/n-Si photodetector with high on/off ratio for detecting very low optical signal

Abstract

In this work, a light-sensitive photodetector based on ZrO2 nanofibers (NFs) formed onto n-Si derived by the electrospinning technique was reported. According to the I–V measurements in the dark, the ZrO2 NFs/n-Si has an ohmic current conduction mechanism at low voltages and the SCLC conduction mechanism at medium voltages, while the Fowler–Nordheim tunneling conduction model is dominant at high voltages. The dark current and the rectifying ratio were found to be 9.4 × 10−10 A (at −1.0 V) and 10 351 (at ±1.0 V), respectively. The shunt resistance (R sh) (at −1 V) and series resistance (R s) (at +2 V) values were determined as 2.0 GΩ and 5.5 kΩ, respectively from the dark I–V plot. The device was shown to be highly sensitive to light and exhibits self-powering characteristics under illumination. The ON/OFF ratio was about 1.0 × 106 at zero-bias (self-powered mode) suggested a good response of the device to the light intensity. The maximum responsivity and specific detectivity were calculated to be 1.44 mA W−1 and 4.5 × 108 Jones, respectively. Finally, capacitance and conductance versus bias voltage characteristics of the device were analyzed at various frequencies.