Effect of gold nanoparticles on the optoelectronic properties of oxygen-deficient ZnO thin films

Gold nanoparticles (AuNPs) were incorporated beneath the electron-beam evaporated ZnO thin films. The thin films were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, Raman spectroscopy and photoluminescence spectroscopy (PL). The combined results of PL and Raman indicated the existence of many point defects in the bare ZnO film itself including the presence of oxygen vacancy. The red shift in one of the prominent Raman modes at 562 cm(-1) (from the usually observed position of 574 cm(-1)) indicated the existence of tensile stress in the films. Due to the presence of AuNPs, whereas PL emissions showed Burstein-Moss effect, Raman spectra showed SERS effect. The carrier concentration was found to increase from - 9 x 10(21) m(-3) for bare ZnO/glass to similar to 26 x 10(22) m(-3) for ZnO/AuNPs/glass. The study of electrical properties indicates that photoconductivity of ZnO thin films can be easily controlled by simply incorporating the tunable AuNPs underneath. Unlike many recent studies on AuNPs-ZnO heterostructures, the present study proposes simple method to incorporate AuNPs to control the properties of ZnO in thin film form. This study will add to the research on optoelectronics.

Automated summary

Gold nanoparticles (AuNPs) were incorporated beneath the ZnO thin films and were found to affect the electrical and optical properties of the films. The presence of AuNPs increased the carrier concentration and the films exhibited different emission and Raman spectra. This study provides a simple method to control the properties of ZnO thin films by incorporating AuNPs.