Related Experiment Video
Updated: Feb 2, 2026
10:45
Fabrication of a Solution-gated Indium-Tin-Oxide-based One-piece Transistor Enabling Sensitive Biosensing
Published on: August 29, 2025
706
Improved pH Sensitivity and Reliability for Extended Gate Field-Effect Transistor Sensors Using High-k Sensing
1Department of Electronic Materials Engineering, Kwangwoon University, 20 Kwangwoon-ro, Nowon-Gu, Seoul 01897, Republic of Korea.
Journal of Nanoscience and Nanotechnology
|November 25, 2018
Summary
This study developed dual-gate field-effect transistor (FET) pH sensors. Tantalum oxide (Ta₂O₅) membranes achieved high sensitivity (478 mV/pH), surpassing the Nernst limit for biosensor applications.
Area of Science:
- Materials Science
- Electrical Engineering
- Analytical Chemistry
Background:
- Conventional ion-selective field-effect transistor (ISFET) sensors have a theoretical sensitivity limit of 59 mV/pH.
- Extended-gate (EG) field-effect transistors (FETs) offer a platform for enhanced sensor design.
- Improving the sensitivity and stability of pH sensors is crucial for advanced biosensing.
Purpose of the Study:
- To fabricate and evaluate dual-gate (DG) FET pH sensors with various dielectric sensing membranes.
- To investigate the impact of different dielectric materials on sensor sensitivity and performance.
- To achieve pH sensing sensitivity beyond the Nernst limit using capacitive coupling.
Main Methods:
- Fabrication of extended-gate (EG) field-effect transistors (FETs) using silicon-on-insulator (SOI) metal-oxide semiconductor field-effect transistor (MOSFET) technology.
- Integration of different dielectric sensing membranes: silicon dioxide (SiO₂), silicon nitride (Si₃N₄), hafnium oxide (HfO₂), and tantalum pentoxide (Ta₂O₅).
- Characterization of sensor performance, including sensitivity, hysteresis, and drift rate, utilizing capacitive coupling for signal amplification.
Main Results:
- The dual-gate (DG) FET configuration successfully amplified sensor sensitivity beyond the 59 mV/pH Nernst limit.
- The sensor utilizing a tantalum pentoxide (Ta₂O₅) membrane exhibited the highest sensitivity at 478 mV/pH.
- The Ta₂O₅ membrane also demonstrated favorable low hysteresis (100.2 mV) and drift rate (24.6 mV/h).
Conclusions:
- Dual-gate (DG) FET structures with extended-gate (EG) configurations can significantly enhance pH sensor sensitivity.
- Tantalum pentoxide (Ta₂O₅) is a promising dielectric material for high-performance pH sensing membranes.
- The developed Ta₂O₅-based DG FET pH sensors meet critical requirements for sensitivity, stability, and reliability in biosensor applications.
More Related Videos
Related Concept Videos
01:29Field Effect Transistor
1.2K
Field-effect transistors (FETs) are integral to electronic circuits and distinguished by their three-terminal setup: the gate, drain, and source. These transistors operate as unipolar devices, which utilize either electrons or holes as charge carriers, in contrast to bipolar transistors, which use both types of carriers. The primary function of the FET is to modulate the flow of these carriers from the source to the drain through a channel. The voltage difference between the gate and source...
1.2K
01:29Reliability and Validity
13.9K
Reliability and validity are two important considerations that must be made with any type of data collection. Reliability refers to the ability to consistently produce a given result. In the context of psychological research, this would mean that any instruments or tools used to collect data do so in consistent, reproducible ways.
13.9K
02:57The Sense of Self: Reflected Self-Appraisal and Social Comparison
56.1K
According to Charles Cooley, we base our image on what we think other people see (Cooley 1902). We imagine how we must appear to others, then react to this speculation. We don certain clothes, prepare our hair in a particular manner, wear makeup, use cologne, and the like—all with the notion that our presentation of ourselves is going to affect how others perceive us. We expect a certain reaction, and, if lucky, we get the one we desire and feel good about it. But more than that, Cooley...
56.1K
01:22Bipolar Junction Transistor
1.5K
Bipolar Junction Transistors (BJTs) are essential elements in electronic circuits, playing a crucial role in the functionality of amplifiers, memories, and microprocessors. These transistors can be designed as NPN or PNP based on their doping patterns. They consist of three layers: the emitter, base, and collector. The configuration of these layers and their respective doping levels—with N-type or P-type impurities—define the transistor's type and its operational...
1.5K
01:30Underflow Gates
413
Underflow gates are vital for controlling water flow in irrigation canals. The three main types of underflow gates — vertical, radial, and drum gates — serve different purposes while ensuring effective flow management. Vertical gates move up and down, generating a free-flowing water jet; radial gates pivot to regulate the flow; and drum gates rotate for precise adjustments. The flow through these gates is influenced by downstream conditions, resulting in free or drowned outflow.Free and...
413
01:30Ligand-Gated Ion Channel Receptor: Gating Mechanism
4.0K
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
4.0K