The effect of vanadium oxide thin films on the detection properties of optical sensors

In this work, Au/n-Si an Au/VOx/n-Si samples were produced to investigate diode parameters of VOx interface effect. Thin films were deposited using the magnetron sputtering system. Surface morphology of the device was observed using SEM and structural characterization were explored using XRD and EDS. These analyses showed deposited VOx thin film coated on n-Si surface homogenously. The capacitance-voltage (C-V) and conductance-voltage characteristics of Au/VOx/n-Si/Au device were measured in the frequency range of 5 kHz to 1 MHz between +4V and -4V bias voltages at room temperature. The experimental results showed that, the electrical properties of Au/VOx/n-Si/Au device has a close relationship with frequency and the bias voltage. The capacitance value of the device increased from 2.5x10-9 F to 4.5x10-9 F with the effect of VOx and as a result of capacitance increase, the dielectric constant increased from 3000 to 5000. In addition, C-V and G-V measurements were performed between frequency range of 1 kHz-1MHz and temperature range of 300 K- 500 K and seen that, the device performance is related with temperature. For the purpose of comparison, two structures have been created and the metal oxide structure can be used successfully as a device which has a high dielectric coefficient with the effect of VOx. The photocurrent (Iph) value increased with the effect of the VOx interface material, especially in the wavelength range of 380-480 nm, and the response to light, especially with the effect of the interface material, reached its peak, especially at the wavelength of 480 nm. Considering all the results, it is understood that the Vanadium Oxide interface material has a positive effect on the diode parameters of the structure and this structure can be used as a photo sensor.