Gd-Doped ITO Thin Films: A Comprehensive Study of Their Optical, Electrical, and Magnetic Properties

Transparent conductive oxides (TCO) have attracted a lot of attention during the past few decades due to their significant contribution to electro optical applications, including flat panel displays, solar cells, LEDs, and wearable electronics. In this study, we use Indium Tin Oxide (ITO) thin films as a prominent TCO, dope it with various amounts of Gadolinium (Gd) and investigate the optical, electrical, and magnetic properties of them. We aim to incorporate magnetism into our TCO samples and make a channel between electro optical and magnetic application. A series of ten Gd-ITO films with varying Gd concentrations were prepared by DC magnetron co-sputtering of ITO and Gd targets in argon. The Gd atomic concentration of each film was determined by EDS and ranged from 0% to 20% (metals basis). The films were 1um thick and were oxygen deficient, becoming opaquer as the Gd concentration increased. The film resistivity increases with Gd concentration. Annealing in the air at 500^oC makes the films more transparent and they remain conductive. The film resistivity of the transparent annealed films ranges from ~1×10^-3 ohm-cm (for 0 at% Gd) to ~2×10^-2 ohm-cm (for 20 at% Gd). Gd-doped thin films are subsequently studied using SQUID magnetometry, low temperature photoluminescence, transmission measurements, ellipsometry and x-ray diffraction. Initial findings indicate the potential to create a transparent, conductive, and magnetic thin film of Gd-doped ITO.