AN ABSTRACT OF THE THESIS OF Rick E. Presley for the degree of Master of Science in Electrical Engineering and Computer Science presented on February 27, 2006. Title: Transparent Electronics: Thin-Film Transistors and Integrated Circuits Abstract approved:

approved: John F. Wager This thesis focuses on two aspects of transparent electronics, SnO2 transparent thin-film transistors (TTFTs) and transparent circuits. Both depletionand enhancement-mode SnO2 TTFTs are realized. The maximum effective mobility for the depletionand enhancement-mode devices are 2 cmVs and 0.8 cmVs, respectively. A variety of techniques to decrease the carrier concentration in the SnO2 channel are investigated. However, the only successful technique is to decrease the channel thickness, which effectively decreases the channel conductivity, and is the procedure employed for successful realization of an enhancement-mode TTFT. The second part of this thesis focuses on the fabrication procedure and the electrical characteristics of transparent circuits, which include inverters and ring oscillators. These circuits are highly transparent, exhibiting ∼75% optical transmittance in the visible portion of the electromagnetic spectrum, and are fabricated using indium gallium oxide as the active channel material and standard photolithography techniques. The n-channel indium gallium oxide thin-film transistors exhibit a peak incremental mobility of ∼7 cmVs and a turn-on voltage of ∼2 V. A five-stage ring oscillator circuit (which does not employ level-shifting) is fabricated, and exhibits an oscillation frequency of ∼2.2 kHz with the gate and drain of the load transistor biased at 30 V; the maximum oscillation frequency observed is ∼9.5 kHz, with the gate and drain of the load transistor biased at ∼80 V.