title: Doping GaP Core-Shell Nanowire pn-Junctions: A Study by Off-Axis Electron Holography.
abstract: The doping process in GaP core-shell nanowire pn-junctions using different precursors is evaluated by mapping the nanowires' electrostatic potential distribution by means of off-axis electron holography. Three precursors, triethyltin (TESn), ditertiarybutylselenide, and silane are investigated for n-type doping of nanowire shells; among them, TESn is shown to be the most efficient precursor. Off-axis electron holography reveals higher electrostatic potentials in the regions of nanowire cores grown by the vapor-liquid-solid (VLS) mechanism (axial growth) than the regions grown parasitically by the vapor-solid (VS) mechanism (radial growth), attributed to different incorporation efficiency between VLS and VS of unintentional p-type carbon doping originating from the trimethylgallium precursor. This study shows that off-axis electron holography of doped nanowires is unique in terms of the ability to map the electrostatic potential and thereby the active dopant distribution with high spatial resolution.
authors: Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark.
authors: Sadegh
authors: S
authors: Yazdi
authors: Solid State Physics, Lund University, Box 118, S-221 00, Lund, Sweden.
authors: Alexander
authors: A
authors: Berg
authors: Solid State Physics, Lund University, Box 118, S-221 00, Lund, Sweden.
authors: Magnus T
authors: MT
authors: Borgström
authors: Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark.
authors: Takeshi
authors: T
authors: Kasama
authors: Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark.
authors: Marco
authors: M
authors: Beleggia
authors: Solid State Physics, Lund University, Box 118, S-221 00, Lund, Sweden.
authors: Lars
authors: L
authors: Samuelson
authors: Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark.
authors: Jakob B
authors: JB
authors: Wagner
keywords: core-shell nanowires; electron holography; electrostatic potential; gallium phosphide; nanowires, doping; potential maps