Effects of Thermal Annealing on the Properties of Zirconium-Doped MgxZn1-XO Films Obtained through Radio-Frequency Magnetron Sputtering

Zirconium-doped MgxZn1-xO (Zr-doped MZO) mixed-oxide films were investigated, and the temperature sensitivity of their electric and optical properties was characterized. Zr-doped MZO films were deposited through radio-frequency magnetron sputtering using a 4-inch ZnO/MgO/ZrO2 (75/20/5 wt%) target. Hall measurement, X-ray diffraction (XRD), transmittance, and X-ray photoelectron spectroscopy (XPS) data were obtained. The lowest sheet resistance, highest mobility, and highest concentration were 1.30 x 10(3) omega/sq, 4.46 cm(2)/Vs, and 7.28 x 10(19) cm(-3), respectively. The XRD spectra of the as-grown and annealed Zr-doped MZO films contained MgxZn1-xO(002) and ZrO2(200) coupled with Mg(OH)(2)(101) at 34.49 degrees, 34.88 degrees, and 38.017 degrees, respectively. The intensity of the XRD peak near 34.88 degrees decreased with temperature because the films that segregated Zr4+ from ZrO2(200) increased. The absorption edges of the films were at approximately 348 nm under 80% transmittance because of the Mg content. XPS revealed that the amount of Zr4+ increased with the annealing temperature. Zr is a potentially promising double donor, providing up to two extra free electrons per ion when used in place of Zn2+.