A comparative study on as-deposited and in situ oxidized ZnO/diamondlike carbon (DLC) nanocomposite by pulsed laser deposition technique

Abstract

As-deposited ZnO/diamondlike carbon (DLC) was prepared using the laser ablation technique on ZnO/C targets, and in situ oxidized ZnO/DLC was prepared by using the same technique, but with the presence of oxygen on Zn/C targets. Transmission electron microscopy showed that ZnO/DLC films were obtainable by using both methods, but only in situ oxidized ZnO/DLC films showed the ultraviolet absorption at ˜370 nm. In situ oxidized films are highly sp3-bonded and rougher than as-deposited films, but as-deposited films are mechanically harder, stiffer, and have higher adhesion strength than in situ oxidized films. X-ray photoelectron spectroscopy revealed that a lower fraction of SiC, but a higher fraction of sp3 bonding was formed in the in situ oxidized ZnO/DLC. This hinted that the presence of oxygen might have scattered the plume’s expansion and reduced the energy possessed by the ions, thus reducing the graphitization and the formation of SiC in DLC matrix. Hence, by altering the deposition mechanism during laser ablation, ZnO/DLC films with modified material properties can be tailored.