Fabrication and Characterization of Self-scrolling Si/Cr Micro- and Nanostructures

Based on self-scrolling of Si/Cr bilayer films on Si(001) wafers, various micro-and nanostructures including micro-claws, microtubes, helical nanobelts, nanorings and nanospirals are fabricated in a controllable way. The scrolling principles of the structures from Si/Cr bilayer films are discussed. The flexibility of individual Si/Cr nanospirals and nanorings has been investigated using a nanorobotic manipulator. It has been found that multiple-turn Si/Cr nanorings exhibit a "sticky force" between neighboring bilayers which is mainly attributed to the van der Waals force. Thus, multiple-turn Si/Cr or SiGe/Si/Cr tubes are self-closing and may be used as pipes for micro-fluidics. Moreover, the excellent elasticity and shape-memory effect of these structures may also be utilized for building MEMS/NEMS devices.