Optical, Electrical, and Magnetic Studies of Gd-Doped ITO Thin Films*

This work investigates the optical, electrical, and magnetic properties of Gadolinium-doped Indium Tin Oxide (ITO) thin films. ITO is a well-known example of a transparent conducting oxide (TCO). Vast developments in flat panel displays, solar cells, LEDs and wearable electronics are outcomes of heavy research on TCOs. These materials are electrically conductive, yet optically transparent due to their large energy band gap. On the other hand, advances in spintronic devices require the introduction of good dilute magnetic semiconductors (DMS). In an effort to produce transparent DMS, Gd-doped ITO films were prepared by simultaneous dc magnetron sputtering from ITO and gadolinium targets. Samples prepared for this investigation were deposited in the absence of excess oxygen to establish conditions that are more favorable for high electrical conductivity. For substrates we used fused silica, silicon, and sapphire. Thin films of ITO doped with various Gd concentrations are then investigated by low temperature photoluminescence, transmission measurements, ellipsometry, SQUID magnetometry and x-ray diffraction. Preliminary results suggest the possibility of fabricating a transparent, conductive, and magnetic thin film of Gd-doped ITO.