Molecular bridge-mediated ultralow-power gas sensing

Abstract We report the electrical detection of captured gases through measurement quantum tunneling characteristics gas-mediated molecular junctions formed across nanogaps. The gas-sensing nanogap device consists a pair vertically stacked gold electrodes separated by an insulating 6 nm spacer (~1.5 sputtered α-Si and ~4.5 ALD SiO 2 ), which is notched ~10 into stack between electrodes. exposed surface functionalized with self-assembled monolayer (SAM) conjugated thiol linker molecules. When to target gas (1,5-diaminopentane), SAM layer electrostatically captures molecules, forming bridge nanogap. capture lowers barrier potential for electron edge region, from ~5 eV ~0.9 establishes additional conducting paths charge transport electrodes, leading substantial decrease in junction resistance. demonstrated output resistance change >10 8 times upon exposure 80 ppm diamine as well ultralow standby power consumption <15 pW, confirming bridges ultralow-power sensing.