Optical study of the band structure of wurtzite GaP nanowires

Journal article (2016)

Authors

S Assali Eindhoven University of Technology
J. Greil Eindhoven University of Technology
I Zardo Eindhoven University of Technology
A. Belabbes Friedrich Schiller University Jena
M.W.A. de Moor Eindhoven University of Technology
Sebastian Koelling Eindhoven University of Technology
P. M. Koenraad Eindhoven University of Technology
F. Bechstedt Friedrich Schiller University Jena
E.P.A.M. Bakkers Kavli institute of nanoscience Delft, Eindhoven University of Technology, QN/Bakkers Lab
Jos E.M. Haverkort Eindhoven University of Technology
Research Group
QN/Bakkers Lab
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Published Date

28-07-2016

Language

English

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Research Group

QN/Bakkers Lab

Abstract

We investigated the optical properties of wurtzite (WZ) GaP nanowires by performing photoluminescence (PL) and time-resolved PL measurements in the temperature range from 4 K to 300 K, together with atom probe tomography to identify residual impurities in the nanowires. At low temperature, the WZ GaP luminescence shows donor-acceptor pair emission at 2.115 eV and 2.088 eV, and Burstein-Moss band-filling continuum between 2.180 and 2.253 eV, resulting in a direct band gap above 2.170 eV. Sharp exciton α-β-γ lines are observed at 2.140-2.164-2.252 eV, respectively, showing clear differences in lifetime, presence of phonon replicas, and temperature-dependence. The excitonic nature of those peaks is critically discussed, leading to a direct band gap of ∼2.190 eV and to a resonant state associated with the γ-line ∼80 meV above the Γ8C conduction band edge.