Microstructural and optical properties of Ta-doped ZnO films prepared by radio frequency magnetron sputtering. Issue 9 (July 2016)

• Record Type: Journal Article
• Authors: Wu, Yongheng; Li, Cuiping; Li, Mingji; Li, Hongji; Xu, Sheng; Wu, Xiaoguo; Yang, Baohe
• Is Part Of: Ceramics international. Volume 42:Issue 9(2016)
• Page Start: 10847
• Page End: 10853
• Publication Date: 2016-07
• Subjects: Ta-doped ZnO film -- Magnetron sputtering -- Optical properties -- Microstructure; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2016.03.214
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Ta-doped ZnO films with different doping levels (0–5.02 at%) were prepared by radio frequency magnetron sputtering. The effects of the doping amount on the microstructure and the optical properties of the films were investigated. The grain size and surface roughness first significantly decrease and then slowly increase with the increase of Ta doping concentration. Both the grain size and the root mean square (RMS) roughness reach their minimum values at the doping content of 3.32 at%. X-ray Diffraction (XRD) patterns confirmed that the prepared Ta-doped ZnO films are polycrystalline with hexagonal wurtzite structure and a preferred orientation along the (002) plane. X-ray photoelectron spectroscopy (XPS) analysis reveals that Ta exists in the ZnO film in the Ta 5+ and Ta 4+ states. The average optical transmission values of the Ta-doped ZnO films are higher than those of the un-doped ZnO film in the visible region. The band gap energy extracted from the absorption edge of transmission spectra becomes large and the near band edge (NBE) emission energy obtained from PL spectra blueshifts to high energy when the Ta doping content grows from 0 at% to 5.02 at%, which can be explained by the Burstein–Moss shift.