Optical Properties of Nanostructured Aluminum Doped Zinc Oxide (ZnO) Thin Film for Thin Film Transistor (TFT) Application

The properties of nanostructured aluminum (Al) doped zinc oxide (ZnO) thin film for thin film transistors (TFT) are presented. This research has been focused on optical and structural properties of Al doped ZnO thin film. The influence of Al doping concentration at 0~5 at.% on the Al doped ZnO thin film properties have been investigated. The thin films were characterized using UV-Vis-NIR spectrophotometer for optical properties. The surface morphology has been characterized using field emission scanning electron microscope (FESEM). The absorption coefficient spectra obtained from UV-Vis-NIR spectrophotometer measurement show all films have low absorbance in visible and near infrared (IR) region but have high UV absorption properties. The calculated Urbach energy indicated the defects concentrations in the thin films increase with doping concentrations The FESEM investigations shows that the nanoparticles size becomes smaller and denser as the doping concentration increase.