Photogating and electrical-gating of amorphous GaSnZnO-based inverter with light-transmitting gate electrode

Abstract

Photoinverter and electrical-inverter applications of amorphous GaSnZnO thin-film transistors (GTZO-TFTs) with Al2 O3 dielectrics were studied. The inverters were composed of two serially connected top-gate GTZO-TFTs with different gate electrodes: semitransparent conducting NiO x and opaque Al. Since the two electrodes have so different work functions as to properly arrange the respective threshold voltages of driver and load TFTs, our inverter exhibited a desirable voltage transfer characteristics with voltage gain of over 25 for electrical gating. A dynamic photogating was demonstrated with an output photogain of ∼2 V as we applied a blue illumination onto semitransparent NiOx gate, through which the photons are transmitted to excite the trapped electrons at the Al2 O3 dielectric/GTZO channel interface. © 2011 American Institute of Physics.