“…As it is evident from previous reports, the Ag-doped ZnO films have preferred orientation in the (0 0 2) direction [6,7,9,13,15,19,30]. Because Ag + ions have larger radius (0.122 nm) than Zn 2+ (0.074 nm), they either substitute ions of Zn 2+ leading to the distortion of unit cell or segregate at the grain boundaries of ZnO and hence induce considerable disorder and faster grow of ZnO grains [19,30].…”