Molecular bridge-mediated ultralow-power gas sensingopen access
- Banerjee, Aishwaryadev; Khan, Shakir-Ul Haque; Broadbent, Samuel; Bulbul, Ashrafuzzaman; Kim, Kyeong Heon; Noh, Seungbeom; Looper, R.; Mastrangelo, C. H.; Kim, H.
- Issue Date
- MICROSYSTEMS & NANOENGINEERING, v.7, no.1
- Journal Title
- MICROSYSTEMS & NANOENGINEERING
- We report the electrical detection of captured gases through measurement of the quantum tunneling characteristics of gas-mediated molecular junctions formed across nanogaps. The gas-sensing nanogap device consists of a pair of vertically stacked gold electrodes separated by an insulating 6 nm spacer (similar to 1.5 nm of sputtered alpha-Si and similar to 4.5 nm ALD SiO2), which is notched similar to 10 nm into the stack between the gold electrodes. The exposed gold surface is functionalized with a self-assembled monolayer (SAM) of conjugated thiol linker molecules. When the device is exposed to a target gas (1,5-diaminopentane), the SAM layer electrostatically captures the target gas molecules, forming a molecular bridge across the nanogap. The gas capture lowers the barrier potential for electron tunneling across the notched edge region, from similar to 5 eV to similar to 0.9 eV and establishes additional conducting paths for charge transport between the gold electrodes, leading to a substantial decrease in junction resistance. We demonstrated an output resistance change of >10(8) times upon exposure to 80 ppm diamine target gas as well as ultralow standby power consumption of <15 pW, confirming electron tunneling through molecular bridges for ultralow-power gas sensing.
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- 융합기술공과대학 > Division of Converged Electronic Engineering > Journal Articles
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