Photoconductive UV detectors based heterostructures of Cd and Mg doped ZnO sol gel thin films

The photoconductive properties of single (CdZnO/MgZnO, Li:CdZnO/MgZnO) and double (MgZnOgnO/MgZnO, CdZnO/ZnO/MgZnO) heterostructures were studied by sol gel method at different annealing temperatures. These structures were analysed by X-ray diffraction (XRD) and photoluminescence (PL). The photoconductive measurements were carried out by semiconductor parametric analyzer. The hexagonal wurtzite structure was retained with good crystalline nature. The UV related strong near band edge (NBE) emission, ultra violet and blue green emission peaks were observed from PL spectra. Photocurrent was observed to have enhanced as a result of annealing temperature and Li substitution in the doped ZnO lattice. The increase of responsivity at ten orders of magnitude was found. Meanwhile, the dark current was found to have increased slightly due to the adsorption of O-2 and H2O molecule on the surface of the film. Sub-linear behaviour of photocurrent was also observed. (C) 2014 Elsevier B.V. All rights reserved.