Effects of oxygen partial pressure on the characteristics of magnetron-sputtered ZnMgBeO thin films

• Published in: Applied surface science 2015-11, Vol.355, p.582-586
• Main Authors: Cuong, Hoang Ba, Lee, Byung-Teak
• Format: Article
• Language: English
• Subjects: Density; Electrical properties; Grain size; Magnetic properties; Optical properties; Oxygen effects; Partial pressure; Thin films; UV detector; X-ray photoelectron spectroscopy; ZnMgBeO; ZnO
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2015.07.051

•Bandgap values of ZnMgBeO films decrease with the oxygen addition ([O2]).•Zn concentration within the films significantly increases with the oxygen addition.•The (0002) peak FWHM decreases with small [O2] and then increases with further addition.•High density of oxygen vacancies exists in the ZnMgBeO films grown in pure Ar plasma.•TEM shows grain sizes increase with initial oxygen addition but then decrease with further addition. Effects of oxygen partial pressure within the Ar process plasma on the optical, structural, and electrical properties of magnetron-sputtered ZnMgBeO films were investigated in detail. It was observed that the optical energy bandgap (Eg) values of the ZnMgBeO films substantially decrease with the oxygen addition, from 5.3 to 4.3eV as the oxygen partial pressure increases from zero to one. The full-width-at-half-maximum (FWHM) values of the (0002) XRD peaks drastically decrease with the addition of a small amount of oxygen but then increase with further oxygen addition. All the films had very high sheet resistance, 1.3–1.4GΩ/□. It was also observed that the concentration of Zn within the films significantly increased with the oxygen addition, which was proposed to be mainly responsible for the observed decrease in Eg. It was also proposed that the FWHM change due to the oxygen addition may be attributable to three factors, film composition, grain size, and point defect density, as confirmed by results of TEM and XPS investigations.