Abstract This study demonstrates an improvement in the photodetection response of a Cupric Oxide (CuO) thin film through the annealing process. The CuO thin film was deposited on silicon substrate using DC magnetron sputtering system. Annealing of the as-deposited film was carried out in a muffle furnace at 400 and 500 °C for two hours. X-ray diffraction patterns revealed the formation of a single phase CuO film whose crystallinity was improved with increase of the annealing temperature. The field emission scanning electron microscopy indicated a compact and fine granular structure of the as-deposited film whereas the segregation and agglomeration of grains was observed after the film’s annealing. The photodetection performance of CuO film with Al contacts was investigated under the exposure of visible light. The current–voltage graphs of as-deposited and annealed films displayed Schottky contact between the metal and semiconductor, owing to a lower work function of Al than that of the CuO. The photo-to-dark current ratio of the device was significantly enhanced after the film’s annealing. The increase in photocurrent became more pronounced upon increasing the light intensity from 58 to 511 µW/cm2. The maximum current gain and sensitivity values were found to be 66 and 6500% respectively at 10 V bias for the film annealed at 500 °C. The rise and fall time of the Al/CuO/Al photodetector was decreased after the film’s annealing.
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