Influence of aluminum dopant on the structural and optical properties of zinc oxide colloids prepared by sol-gel spin coating method

Doped zinc oxide (ZnO) colloids have attracted significant attention recently due to its wide range of applications owing to the effective tunable properties and remarkable solution processability. In this work, low cost sol-gel spin coating technique was employed to synthesize the aluminum doped ZnO colloids (AZO). The influences of the Al doping concentration on the structural and optical properties of the AZO colloids were investigated using field-emission scanning electron microscopy (FESEM), ultraviolet-visible (UV-Vis) spectrophotometer and photoluminescence (PL) spectroscopy. Elemental composition was confirmed using energy dispersive X-Ray spectrophotometer (EDX). The size of colloid particles decrease from approximately 400 nm to 100 nm as the Al doping concentration is increased. As the size of the colloids decrease, the position of absorption peak was blue shifted, whilst the tunable optical band gap (Eg) of the AZO colloids is profound.