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

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 x 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 G omega and 5.5 k omega, 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 x 10(6) 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 x 10(8) Jones, respectively. Finally, capacitance and conductance versus bias voltage characteristics of the device were analyzed at various frequencies.