Sputtered cobalt doped CuO nano-structured thin films for photoconductive sensors

Pure and cobalt (Co) doped CuO thin films have been deposited by DC and AC reactive magnetron sputtering technique. The doping ratio has been controlled by the RF power of the AC sputtering unit. The sputtering power ranges from 0 to 50W. The crystal structure of the films has been identified by X-ray diffraction. One of the peaks has been shifted toward the high diffraction angle. Energy dispersive analysis shows cationic deficiency of the pure and doped samples. Morphology of the films has been investigated by atomic force microscopy. Film roughness decrease with the increase of sputtering power. Spectrophotometry studies reveal that films darken with the increase of sputtering power. The current-voltage curves show Ohmic contacts and an enhancement in the conductivity with the increase of Co concentrations. Photoresponse measurements have shown that the film doped at 50W is the best photodetector sensor.