Nanomechanical and microstructural characterization of sputter deposited ZnO thin films

Abstract

The nano-mechanical properties of ZnO thin films deposited at different substrate temperature such as (RT) 25 °C, 100 °C, 200 °C, and 300 °C using DC-sputtering on Corning glass substrate were investigated. The ZnO thin films are found to be predominately c-axis (002) oriented. The crystal structure is sensitive to increasing substrate temperature and new set of crystal planes become visible at 300 °C as thin films become highly polycrystalline. The presence of (103) crystal plane is more pronounced with the increasing substrate temperature. However, high crystallinity and peak intensity ratio I (002) /I (103) (counts) is highest for thin films deposited at 100 °C, which is attributed for high hardness and better adhesive properties observed for ZnO thin films. Concomitantly, no major sudden burst of displacement ‘pop-in’ event in load-displacement curve of thin films observed during indentation, indicating the films are dense with low defects and adhered strongly to the substrate.