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Preparation of Silicon Nanowire Field-effect Transistor for Chemical and Biosensing Applications
Published on: April 21, 2016
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Ion-Step Method for Surface Potential Sensing of Silicon Nanowires
Songyue Chen1, Jan W van Nieuwkasteele2, Albert van den Berg2
1Department of Mechanical and Electrical Engineering, Xiamen University , 361005 Xiamen, China.
Analytical Chemistry
|July 27, 2016
Summary
This study introduces a new method for sensing surface potential in silicon nanowire field-effect transistors using an "ion-step" stimulus. This technique offers a drift-resistant alternative for precise surface potential measurements.
Area of Science:
- Materials Science
- Nanotechnology
- Surface Chemistry
Background:
- Silicon nanowire (Si-NW) field-effect transistors are explored for surface potential sensing.
- A novel stimulus-response method utilizing an 'ion-step' is presented.
- This method leverages changes in double layer capacitance and Si-NW conductance.
Discussion:
- Surface modification with poly-l-lysine alters the surface potential of the Si-NW gate.
- A shift in the point-of-zero charge pH is observed post-modification.
- The ion-step response is measured as a drop in current variation.
Key Insights:
- An ion-step stimulus (low to high ionic strength) is applied via a microfluidic chip.
- A reduction in ion-step response (2 nA to near zero) at pH 5.0 with increased potassium ion concentration (10 mM to 50 mM) indicates a surface potential change of ~12 mV.
- This demonstrates a sensitive method for detecting surface potential shifts.
Outlook:
- The developed method provides a drift-insensitive alternative for surface potential sensing.
- Potential applications in biosensing and chemical sensing platforms.
- Further optimization for real-time monitoring and complex biological systems.
