Extended-Gate Amorphous InGaZnO Thin Film Transistor for Biochemical Sensing
- Resource Type
- Periodical
- Authors
- Lee, J.; Kim, M.J.; Yang, H.; Kim, S.; Yeom, S.; Ryu, G.; Shin, Y.; Sul, O.; Jeong, J.K.; Lee, S.
- Source
- IEEE Sensors Journal IEEE Sensors J. Sensors Journal, IEEE. 21(1):178-184 Jan, 2021
- Subject
- Signal Processing and Analysis
Communication, Networking and Broadcast Technologies
Components, Circuits, Devices and Systems
Robotics and Control Systems
Electrodes
Logic gates
Indium tin oxide
Biosensors
Thin film transistors
Sensor phenomena and characterization
extended-gate field-effect transistors
pH sensors
real-time detection
thin film transistors
- Language
- ISSN
- 1530-437X
1558-1748
2379-9153
We report on a stable and sensitive biochemical sensor based on amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) with a versatile extended-gate electrode used as the sensing membrane. The extended-gate allows the active transistor channel not to be exposed to the ionic analyte and the gate surface may be modified with chemicals or affinity reagents without affecting the operation of the active sensor. The extended-gate a-IGZO TFT was able to detect the pH levels of various solutions based on protonation and deprotonation at the surface of the indium-tin-oxide (ITO) extended-gate electrode achieving a pH dependent threshold voltage shift of 22.8 mV/pH. Highly sensitive and specific protein sensing was achieved for both electrical polarities according to pH values of solutions using the biotin-streptavidin interaction. The extended-gate TFT sensor demonstrated a detection limit for streptavidin down to 10 fM, using the biotin-streptavidin binding on the extended-gate surface. It was also possible to detect changes in the streptavidin concentration in real-time with specificity and repeatability. Since the extended-gate can be easily replaced without affecting the performance of the a-IGZO TFT, this sensor configuration may be utilized for future multifunctional biomolecular sensing and analysis.