Thin film NiO/BaTiO3/ZnO heterojunction diode-based UVC photodetectors

In this work, a P-I-N thin film Al/NiO/BaTiO3/ZnO/ITO heterojunction diode-based UVC detector was fabricated and characterized. The thin film layers were grown by a low-cost and versatile sol-gel spin coating technique. Scanning electron microscopy (SEM) was utilized to assess the thin film surface microstructure. The crystal structure of the surface layer was investigated by x-ray diffraction (XRD). The P-I-N electrical parameters were estimated from the current-voltage characteristics. The effects of ex situ thermal treatment on the device characteristics were evaluated. The untreated diode showed poor rectifying behavior, and the optimum characteristics were presented by the device treated at 100 degrees C. The P-I-N photodetection capability was studied in the dark and under different optical power radiation levels ranging from 5.3 to 5.6 mW. The photodetection response of the devices treated at the optimum temperature was investigated. Under 5.57 mW UVC (254 nm) illumination and an applied bias of -1.5 V, the P-I-N device demonstrated a photocurrent, contrast ratio, noise equivalent power, and gain of 2.2 x 10(-2) A, 10, 3.3 x 10(-10) W Hz(-1/2), and 19.4, respectively.