Ultraviolet photodetection properties of a pt contact on a Mg0.1Zn0.9O/ZnO composite film

We report on the ultraviolet (UV) photodetection properties of a Pt contact on a sol-gel Mg0.1Zn0.9O/ZnO composite structure on a glass substrate. In the dark, the current-voltage (I-V) characteristics between the Pt and Ag contacts on the top of the ZnO film were linear while that on the Mg0.1Zn0.9O/ZnO composite film were rectifying, suggesting the formation of a Schottky diode on the latter. The ideality factor, n, and the reverse leakage current density, J (R) , of the Schottky diode were greater than 2 and 2.36 x10(-2) A cm(-2) at -5 V, respectively. Under ultraviolet light, the I-V characteristics become linear. The maximum photo-to-dark current ratio observed was about 63. The composite film showed good sensitivity to UV light with wavelengths of less than 400 nm, though the photoresponse process was found to be slow.