Effect of chlorine doping on electrical and optical properties of ZnO thin films

Chlorine doped ZnO thin films were grown by metal-organic chemical vapour deposition (MOCVD) on sapphire and fused silica substrates. Chlorine is incorporated by substitution of oxygen and acts as a donor, leading to an increase of electron concentration. Transport properties were studied for ZnO thin films with different chlorine content. Hall effect measurements show an increase of electron carrier concentration and a decrease of electron mobility upon increasing the amount of chlorine incorporated in ZnO. The lowest resistivity ρ = 3.6 × 10^{- 3} Ω cm was obtained for layers deposited on sapphire substrate. UV-VIS-NIR spectroscopy has been used for the study of optical properties. For all samples, the optical transmittance in the visible range is greater than 80%. First principles computations were applied in order to examine the change in the band gap of ZnO with Cl doping.