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Molecular bridge-mediated ultralow-power gas sensing
Aishwaryadev Banerjee1, Shakir-Ul Haque Khan1, Samuel Broadbent2
1Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112 USA.
Microsystems & Nanoengineering
|September 27, 2021
Summary
This study demonstrates electrical detection of gases using quantum tunneling in molecular junctions. Gas capture significantly reduces junction resistance, enabling highly sensitive, low-power gas sensing.
Area of Science:
- Nanotechnology
- Electrical Engineering
- Chemical Sensing
Background:
- Molecular junctions and quantum tunneling are key for advanced electronic devices.
- Developing ultrasensitive and low-power gas sensors remains a critical challenge.
Purpose of the Study:
- To report the electrical detection of captured gases via quantum tunneling.
- To demonstrate a novel gas-sensing nanogap device utilizing molecular bridges.
Main Methods:
- Fabrication of a nanogap device with gold electrodes and an insulating spacer.
- Functionalization with self-assembled monolayers (SAMs) for gas molecule capture.
- Measurement of quantum tunneling characteristics before and after gas exposure.
Main Results:
- Formation of gas-mediated molecular bridges across the nanogap upon exposure to 1,5-diaminopentane.
- Lowering of the electron tunneling barrier from ~5 eV to ~0.9 eV.
- Demonstration of a >10^8 resistance change and <15 pW standby power consumption.
Conclusions:
- Gas capture via SAMs enables electrical detection through modulation of quantum tunneling.
- The developed device offers a promising platform for ultralow-power, high-sensitivity gas sensing.
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