title: Electronic and structural differences between wurtzite and zinc blende InAs nanowire surfaces: experiment and theory.
abstract: We determine the detailed differences in geometry and band structure between wurtzite (Wz) and zinc blende (Zb) InAs nanowire (NW) surfaces using scanning tunneling microscopy/spectroscopy and photoemission electron microscopy. By establishing unreconstructed and defect-free surface facets for both Wz and Zb, we can reliably measure differences between valence and conduction band edges, the local vacuum levels, and geometric relaxations to the few-millielectronvolt and few-picometer levels, respectively. Surface and bulk density functional theory calculations agree well with the experimental findings and are used to interpret the results, allowing us to obtain information on both surface and bulk electronic structure. We can thus exclude several previously proposed explanations for the observed differences in conductivity of Wz-Zb NW devices. Instead, fundamental structural differences at the atomic scale and nanoscale that we observed between NW surface facets can explain the device behavior.
authors.affiliation: Department of Physics and The Nanometer Structure Consortium, Lund University , P.O. Box 118, 221 00 Lund, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Hjort
authors.forename: Sebastian
authors.initials: S
authors.lastname: Lehmann
authors.forename: Johan
authors.initials: J
authors.lastname: Knutsson
authors.forename: Alexei A
authors.initials: AA
authors.lastname: Zakharov
authors.forename: Yaojun A
authors.initials: YA
authors.lastname: Du
authors.forename: Sung
authors.initials: S
authors.lastname: Sakong
authors.forename: Rainer
authors.initials: R
authors.lastname: Timm
authors.forename: Gustav
authors.initials: G
authors.lastname: Nylund
authors.forename: Edvin
authors.initials: E
authors.lastname: Lundgren
authors.forename: Peter
authors.initials: P
authors.lastname: Kratzer
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Dick
authors.forename: Anders
authors.initials: A
authors.lastname: Mikkelsen
keywords: InAs nanowire; PEEM; STM; STS; surface; wurtzite