Porous-shaped n-CdZnO/p-Si heterojunctions for UV photodetectors.

In this study, n-type Cd_yZn_1−yO (y = 0, 0.5, 1, 1.5 at%) thin films were deposited on p-Si and soda lime glass substrates using sol–gel spin coating technique. From the X-ray diffraction patterns, it was observed that all thin films had wurtzite structure with (002) orientation. Scanning electron micrograph results revealed that the morphology varied with higher Cd doping in ZnO. The bandgap was decreased from 3.29 eV (undoped ZnO) to 3.26 eV (y = 1.5 at%) as Cd content increased. The electronic parameters of the Cd_yZn_1−yO (y = 1 at%) thin film heterojunction such as ideality factor (η) and barrier height (Φ_B) were obtained using the thermionic emission theory as 2.53 and 0.70 eV, respectively. Cd_yZn_1−yO (y = 1 at%) showed responsivity 0.01 A/W on 3.2 mW/cm² exposure of UV light (365 nm) at 4 V bias voltage. The heterojunction so formed seems to be an excellent candidate to be used as an optical sensor (UV photodetector) in optoelectronics. [ABSTRACT FROM AUTHOR]