[13p-N322-1~16] 12.7 Biomedical Engineering and Biochips

▼ [13p-N322-9] Electrical characteristics of solution-gated ultrathin channel ITO-based transistor fabricated by one-step procedure and biomolecular recognition based on its chemical modification

〇(M1)Xianqi Dong¹, Akiko Saito¹, Toshiya Sakata¹ (1.The Univ. of Tokyo)

Keywords:solution-gated field-effect transistor, biosensor

We previously proposed a one-step procedure for fabricating a solution-gated ultrathin channel indium tin oxide (ITO)-based field-effect transistor (FET) biosensor. Owing to a modified metal shadow mask, a thin ITO channel and thick ITO source/drain electrodes were simultaneously fabricated during the one-step sputtering. The thickness of ITO films was critical for them to be semiconductive, depending on the maximum depletion width, similarly to 2D materials. The ultrathin ITO channel worked as an ion-sensitive membrane as well, owing to the intrinsic oxidated surface directly contacting with an electrolyte solution. The solution-gated 20-nm-thick channel ITO-based FET, with a steep subthreshold slope (SS) of 55 mV per decade (pH 7.41) attributable to the electric double-layer capacitance at the electrolyte solution/channel interface and the absence of interfacial traps among electrodes formed in one step, demonstrated an ideal pH responsivity. Therefore, the chemical modification of the ITO channel surface is expected to contribute to biomolecular recognition with ultrahigh sensitivity owing to the remarkably steep SS.