Extended-Gate pH Sensors Using Self-Aligned Four-Terminal Metal Double-Gate Low-Temperature Polycrystalline-Silicon Thin-Film Transistors on Glass Substrate

Abstract

This study evaluates pH sensors using self-aligned four-terminal planar embedded metal double-gate low-temperature polycrystalline-silicon thin-film transistors (TFTs) on a glass substrate. The voltage variation caused by a change in pH was read as a variation in the threshold voltage of the TFTs by connecting the control gate of the TFT to a glass electrode. By changing the reference voltage applied to the refrence electrode, our experimentally obtained pH sensitivity values were found to be in agreement with the theoretical pH sensitivity values, and we confirm that these TFTs can successfully perform as pH sensors.