Highly enhanced ultraviolet photoresponse property in Cu-doped and Cu–Li co-doped ZnO films

A highly enhanced ultraviolet (UV) photodetection property has been achieved in 0.1% Cu doped and 0.1% Cu–2% Li co-doped sol–gel ZnO thin films. The 0.1% Cu doped and 0.1% Cu–2% Li co-doped films show UV photosensitivity values (photo-to-dark current ratio) of around 2000 and 5000, respectively, which is one order of magnitude higher than the undoped film. The co-doped film shows a decrease in the photocurrent growth and decay time constants compared with the Cu doped one. The increased photosensitivity indicates that these low-cost doped and co-doped films are promising for UV photodetection applications.