Synthesis and characterization of gold doped zinc oxide nanostructure for biosensor application

Abstract

Zinc oxide (ZnO), a representative of group II-IV metal-oxide semiconductor material with its wide direct band-gap (3.37eV) and high exciton binding energy (60meV) which providing the advantages of their electrical and optical properties. Due to these unique properties, ZnO is widely studied in the current research community. In addition, the fabrication of doped ZnO thin films have been reported could significantly enhance the device sensitivity by Au adsorption. Thus, this work demonstrated the process development of gold doped zinc oxide (Au-ZnO) thin films using sol-gel method. The effect of different Au thickness layer deposited onto ZnO thin films were studied using various characterization method. The structural properties of ZnO thin films before and after modified with Au layer were investigated by using scanning electron microscope (SEM) and energy dispersive x-ray (EDX). The results show that the element existence on the prepared ZnO thin films sample consist the peak of silicon (Si), zinc (Zn) and oxide (O) as well as gold (Au) for Au modified ZnO sample. The optical properties of ZnO thin films and Au-ZnO thin films were also characterized using ultraviolet-visible spectroscopy (UV-VIS). The results indicate the existence of the ZnO characteristic at particular absorbance peak of 380 nm. The formation of Au-ZnO was further confirmed by obtained the characteristic Au absorbance band at wavelength ranged from 500 nm to 600 nm.