Transparent ring oscillator based on indium gallium oxide thin-film transistors

Highly transparent ring oscillators, exhibiting similar to 75% optical transmittance in the visible portion of the electromagnetic spectrum, are fabricated using indium gallium oxide as the active channel material and standard photolithography techniques. The n-channel indium gallium oxide transparent thin-film transistors (TTFTs) exhibit a peak incremental mobility of similar to 7 cm(2) V-1 s(-1) and turn-on voltage of similar to 2 V. A five-stage ring oscillator circuit (which does not employ level-shifting) exhibits an oscillation frequency of similar to 2.2 kHz when the gate and drain of the load transistor are biased at 30 V; the maximum oscillation frequency observed is similar to 9.5 kHz, with the gate and drain of the load transistor biased at similar to 80 V. (c) 2006 Elsevier Ltd. All rights reserved.