title: Mechanism for nanotube formation from self-bending nanofilms driven by atomic-scale surface-stress imbalance.
abstract: We demonstrate, by theoretical analysis and molecular dynamics simulation, a mechanism for fabricating nanotubes by self-bending of nanofilms under intrinsic surface-stress imbalance due to surface reconstruction. A freestanding Si nanofilm may spontaneously bend itself into a nanotube without external stress load, and a bilayer SiGe nanofilm may bend into a nanotube with Ge as the inner layer, opposite of the normal bending configuration defined by misfit strain. Such rolled-up nanotubes can accommodate a high level of strain, even beyond the magnitude of lattice mismatch, greatly modifying the tube electronic and optoelectronic properties.
authors.affiliation: Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, USA.
authors.forename: Ji
authors.initials: J
authors.lastname: Zang
authors.forename: Minghuang
authors.initials: M
authors.lastname: Huang
authors.forename: Feng
authors.initials: F
authors.lastname: Liu