title: Axial-stressed piezoresistive nanobeam for ultrahigh chemomechanical sensitivity to molecular adsorption.
abstract: This study proposes nanothickness piezoresistive double-clamped beams that are used in a double-side adsorbing mode. The axially stressed clamped beam exhibits continually increasing sensitivity as it is thinned down to nanoscale, and the thinning is theoretically without limitation. Sensing experiments to part-per-million levels of trimethylamine vapor well verify the proposal. A 93 nm thick beam sensor exhibits higher than 1 order of magnitude sensitivity compared to typical piezoresistive cantilever sensors, and its chemomechanical sensing resolution is comparable with that obtained by the off-cantilever optical detection method. With the nanobeam, a surprisingly ultrahigh sensitivity to surface molecular self-assembly induced surface stress is also obtained that is about 150 times higher than that obtained from a conventional cantilever. With additional advantages of elimination of single-sided adsorption induced bimetallic effect noise, tinier size, and easier fabrication, the ultrasensitive nanothick beam sensors show promise to replace the state-of-the-art piezoresistive cantilevers for bio/chemical nanomechanical detection.
authors.affiliation: State Key Lab of Transducer Technology, and Science and Technology on Microsystem Lab, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Chen
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Xu
authors.forename: Xinxin
authors.initials: X
authors.lastname: Li
mesh_terms: D000327:Adsorption; D008744:Methylamines / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology / Q000295:instrumentation; D012825:Silicon / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties
chemical_list: D008744:Methylamines; D012822:Silicon Dioxide; C023336:trimethylamine; D012825:Silicon