Structural and Optical Properties of Gold Nanoparticle Embedded Solution Processed Zinc Oxide Thin Films

Abstract

This thesis deals with the growth and characterisation of gold nanoparticle embedded ZnO thin films. ZnO thin films were synthesised by solution process using reagents like zinc acetate dihydrate, 2-methoxyethanol and monoethanolamine. Parameters like ageing period, annealing duration and number of layers were changed to optimise the growth. Gold nanoparticles were prepared by the direct current sputtering route. Amount of gold was changed to observe its effect on the films. The properties of the so formed films was checked by Thermogavimetric analysis/Differential Scanning Calorimetry (TGA/DSC), X-ray Diffraction (XRD), UV-Vis spectroscopy and Scanning Electron Microscopy (SEM) characterisation. The formation of the ZnO solution is studied from TGA/DSC analysis. It gave decomposition peaks and boiling points of all the reagents and the solution. Detailed structural analysis was carried out by the XRD measurements. The XRD patterns exhibited peaks from various planes of wurtzite ZnO and FCC Au. The SEM studies showed a change in surface ,morphology of the films when Au particles were introduced in the sandwich structure. Optical features were tested by UV-Vis spectroscopy. It showed clear absorption peaks due to the surface plasmon resonance (SPR) of Au nanoparticles suggesting that annealing led to the dewetting and agglomeration of the Au layer. The SPR peak position shifted depending on the annealing duration showing tuning of the optical properties of the sandwich structure.