Fabrication of n-TO2/p-Si Photo-Diodes for Self-Powered Fast Ultraviolet Photodetectors

Fabrication of n-TiO2/p-Si heterojunction devices for the fast solar-blind self-powered ultraviolet photodetectors has been reported. To produce these devices, n-type TiO2 thin films of thickness 50 nm and 200 nm have been deposited by radiofrequency magnetron sputtering technique on p-type silicon substrates. X-ray diffraction (XRD) studies reveal the growth of anatase phase of TiO2 and the scanning electron microscopy (SEM) studies confirm the deposition of rod-like nanostructures of TiO2 of length about 10 mu m and diameter 1 mu m. The current-voltage (I-V) characteristics of the prepared heterojunction devices demonstrate the non-ohmic diode like behavior. The obtained values of ideality factor from I-V characteristics for both the devices are greater than 2, which suggest a trap states assisted space charge limited current (SCLC) conduction of charge transport. The I-V characteristics recorded under the illumination of UV-A radiations (lambda approximate to 365 nm), demonstrate the photodiode like behavior of the fabricated devices. The transient photoresponse of the fabricated devices of thickness 50 nm and 200 nm of TiO2 films, recorded under zero bias conditions are as high as similar to 795% and 180% respectively. The response and recovery times less than unity suggest the fast photodetection ability of the fabricated devices for the next generation photodetectors.

Automated summary

Fabrication and characterization of n-TiO2/p-Si heterojunction devices for fast solar-blind self-powered ultraviolet photodetection have been reported. The devices exhibit good performance in terms of photodiode behavior under UV-A radiation.