Title :
Low-Cost pH Sensors Based on Low-Voltage Oxide-Based Electric-Double-Layer Thin Film Transistors
Author :
Ning Liu ; Yanghui Liu ; Liqiang Zhu ; Yi Shi ; Qing Wan
Author_Institution :
Sch. of Electron. Sci. & Eng., Nanjing Univ., Nanjing, China
Abstract :
Indium-tin-oxide-based electric-double-layer (EDL) thin-film transistors (TFTs) are used as pH sensors. Such EDL devices show a low operation voltage of ~ 1.5 V and a high field-effect electron mobility (μFE) of ~ 20 cm2·V-1·s-1 when phosphorous-doped nanogranular SiO2-based electrolyte films are used as the gate dielectric. The pH sensor based on such EDL TFT exhibits a high sensitivity of 58.1 mV·pH-1 and a good linearity in the pH range from 2 to 12. In addition, such pH sensors present a low threshold voltage drift rate of 2.2 mV·h-1 and a hysteresis voltage of 8.3 mV after a pH loop of 7→ 4→ 7→ 10→7.
Keywords :
chemical sensors; indium compounds; low-power electronics; pH measurement; solid electrolytes; thin film transistors; EDL TFT; InSnO; SiO2; electric-double-layer thin film transistors; electrolyte films; field effect electron mobility; gate dielectric; low threshold voltage drift rate; pH sensors; voltage 8.3 mV; Indium tin oxide; Logic gates; Sensitivity; Sensor phenomena and characterization; Thin film transistors; Oxide-based EDL transistors; P-doped nanogranular ${rm SiO}_{2}$ electrolyte; pH sensor;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2014.2303074
