Effect of fluorine doping on structural, electrical and optical properties of ZnO thin films

We studied effect of fluorine doping on ZnO thin films prepared using chemical spray pyrolysis technique. Structural, electrical and optical characterization techniques were used for the study. Both doped and undoped films showed preferential orientation along (0 0 2) plane. Optical absorption studies indicated a decrease of energy band gap and optical transmission increased with increase in fluorine doping. PL spectrum of undoped sample has a single broad peak at 517 nm while three additional peaks appeared for fluorine-doped film. Electrical resistivity and photosensitivity decreased considerably on doping. Temperature dependent conductivity studies revealed that prominent shallow donor levels are Zn in interstitial and regular lattice positions.