title: Nanomechanical actuation of a silicon cantilever using an azo dye, self-assembled monolayer.
abstract: The emerging fields of nanomotors and optomechanics are based on the harnessing of light to generate force. However, our ability to detect small surface stresses is limited by temperature drift, environmental noise, and low-frequency flicker electronic noise. To address these limitations, we functionalized microfabricated silicon cantilevers with an azo dye, silane-based self-assembled monolayer and modulated the surface stress by exciting the optical switch with a 405-nm laser. Atomic force microscopy, contact angle analysis, ellipsometry, and X-ray photoelectron spectroscopy verified successful assembly of molecules on the cantilever. Ultraviolet and visible spectra demonstrate optical switching of the synthesized molecule in solution. By turning the laser on and off at a specific rate (e.g., 1 Hz), the cantilever deflection can be measured via Fourier techniques, thus separating the signal of interest from the noise. This technique empowers the design of highly sensitive surface stress measurements.
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: A Joseph
authors.initials: AJ
authors.lastname: Rastegar
authors.forename: Michael
authors.initials: M
authors.lastname: Vosgueritchian
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Doll
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Mallon
authors.forename: Beth L
authors.initials: BL
authors.lastname: Pruitt
mesh_terms: D001391:Azo Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D004396:Coloring Agents / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D036103:Nanotechnology / Q000295:instrumentation*; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D012825:Silicon