title: Carrier lifetime and mobility enhancement in nearly defect-free core-shell nanowires measured using time-resolved terahertz spectroscopy.
abstract: We have used transient terahertz photoconductivity measurements to assess the efficacy of two-temperature growth and core-shell encapsulation techniques on the electronic properties of GaAs nanowires. We demonstrate that two-temperature growth of the GaAs core leads to an almost doubling in charge-carrier mobility and a tripling of carrier lifetime. In addition, overcoating the GaAs core with a larger-bandgap material is shown to reduce the density of surface traps by 82%, thereby enhancing the charge conductivity.
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom.
authors.forename: Patrick
authors.initials: P
authors.lastname: Parkinson
authors.forename: Hannah J
authors.initials: HJ
authors.lastname: Joyce
authors.forename: Qiang
authors.initials: Q
authors.lastname: Gao
authors.forename: Hark Hoe
authors.initials: HH
authors.lastname: Tan
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Jin
authors.initials: J
authors.lastname: Zou
authors.forename: Chennupati
authors.initials: C
authors.lastname: Jagadish
authors.forename: Laura M
authors.initials: LM
authors.lastname: Herz
authors.forename: Michael B
authors.initials: MB
authors.lastname: Johnston
mesh_terms: D001152:Arsenicals / Q000737:chemistry*; D004553:Electric Conductivity; D005708:Gallium / Q000737:chemistry*; D008422:Materials Testing; D036103:Nanotechnology / Q000379:methods*; D053770:Nanowires / Q000737:chemistry*; D010316:Particle Size; D010777:Photochemistry; D013499:Surface Properties; D013696:Temperature; D055068:Terahertz Spectroscopy / Q000379:methods*; D013997:Time Factors
chemical_list: D001152:Arsenicals; C043055:gallium arsenide; D005708:Gallium