title: Oscillatory band gap behavior in small diameter Si-clathrate nanowires.
abstract: Electronic structure analysis of small cagelike silicon nanowires is carried out and reveals many surprising features. The band gap values for all the nanowires are found to be smaller than their bulk counterparts. The most intriguing aspect appears to be the alternating sequence of direct and indirect band gaps as the diameter changes. This is attributed to the type of surface geometry. We illustrate this with two well-known clathrate forms as well as a new hexagonal clathrate structure with a direct band gap in the optical region.
authors.affiliation: Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, USA. iponoma@uark.edu
authors.forename: Inna
authors.initials: I
authors.lastname: Ponomareva
authors.forename: Ernst
authors.initials: E
authors.lastname: Richter
authors.forename: Antonis N
authors.initials: AN
authors.lastname: Andriotis
authors.forename: Madhu
authors.initials: M
authors.lastname: Menon
mesh_terms: D003460:Crystallization; D019281:Dimerization; D004581:Electronics; D004583:Electrons; D053768:Metal Nanoparticles / Q000737:chemistry*; D008670:Metals; D008968:Molecular Conformation; D053758:Nanoparticles; D036103:Nanotechnology / Q000379:methods*; D053770:Nanowires / Q000737:chemistry*; D009991:Oscillometry; D012825:Silicon / Q000737:chemistry*
chemical_list: D008670:Metals; D012825:Silicon