Wei-Sheng Liu

Investigation of the Optoelectronic Properties of Ti-doped Indium Tin Oxide Thin Film

In this study, direct-current magnetron sputtering was used to fabricate Ti-doped indium tin oxide (ITO) thin films. The sputtering power during the 350-nm-thick thin-film production process was fixed at 100 W with substrate temperatures increasing from room temperature to 500 °C. The Ti-doped ITO thin films exhibited superior thin-film resistivity (1.5 × 10−4 Ω/cm), carrier concentration (4.1 × 1021 cm−3), carrier mobility (10 cm2/Vs), and mean visible-light transmittance (90%) at wavelengths of 400–800 nm at a deposition temperature of 400 °C. The superior carrier concentration of the Ti-doped ITO alloys (>1021 cm−3) with a high figure of merit (81.1 × 10−3 Ω−1) demonstrate the pronounced contribution of Ti doping, indicating their high suitability for application in optoelectronic devices.

Physical properties of Al-doped MgZnO film grown by RF magnetron sputtering using ZnO/MgO/Al2O3 target

This study investigates the physical properties of Al-doped MgxZn1-xO (AMZO) films. Al-doped MgxZn1-xO films were deposited by radio-frequency (RF) magnetron sputtering system using a 4 inch ZnO/MgO/Al2O3 (76/19/5 wt%) target. This study determined the resulting x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Hall measurement, and transparent performance of the films. XRD results indicate that the diffraction angles of the annealed AMZO film shifted toward the high-angle side, indicating that thermal annealing could relax the compressive strain components in the as-deposited samples. XPS results reveal a high carbon content on the surface of MgxZn1-xO. This may be due to contamination. The average Mg content of the as-grown AMZO is about 19.23 at. % at a depth of 40 nm. The Al-doped MgxZn1-xO film in this study shows high transparency with transmittances over 95 % in the visible region (400 ~ 800nm), and a sharp absorption edge is visible in the UV region due to the Mg content. The Hall measurement of Al-doped MgxZn1-xO films deposited at lower RF power show higher doping concentrations, lower resistivity and higher mobility as a function of the annealing temperature. Experimental results indicate that Al-doped MgxZn1-xO film with 1000 °C annealing contains more oxygen vacancies, which play the role of donor. Oxygen vacancies generate states in the band gap and increase conductivity.