title: Effect of growth orientation and diameter on the elasticity of GaN nanowires. A combined in situ TEM and atomistic modeling investigation.
abstract: We characterized the elastic properties of GaN nanowires grown along different crystallographic orientations. In situ transmission electron microscopy tensile tests were conducted using a MEMS-based nanoscale testing system. Complementary atomistic simulations were performed using density functional theory and molecular dynamics. Our work establishes that elasticity size dependence is limited to nanowires with diameters smaller than 20 nm. For larger diameters, the elastic modulus converges to the bulk values of 300 GPa for c-axis and 267 GPa for a- and m-axis.
authors.affiliation: Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208-3111, USA.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Bernal
authors.forename: Ravi
authors.initials: R
authors.lastname: Agrawal
authors.forename: Bei
authors.initials: B
authors.lastname: Peng
authors.forename: Kristine A
authors.initials: KA
authors.lastname: Bertness
authors.forename: Norman A
authors.initials: NA
authors.lastname: Sanford
authors.forename: Albert V
authors.initials: AV
authors.lastname: Davydov
authors.forename: Horacio D
authors.initials: HD
authors.lastname: Espinosa
mesh_terms: D003198:Computer Simulation; D003460:Crystallization / Q000379:methods; D055119:Elastic Modulus; D005708:Gallium / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D010316:Particle Size; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D046911:Macromolecular Substances; C473348:gallium nitride; D005708:Gallium