title: Quantum Confined Stark Effect in a GaAs/AlGaAs Nanowire Quantum Well Tube Device: Probing Exciton Localization.
abstract: In this Letter, we explore the nature of exciton localization in single GaAs/AlGaAs nanowire quantum well tube (QWT) devices using photocurrent (PC) spectroscopy combined with simultaneous photoluminescence (PL) and photoluminescence excitation (PLE) measurements. Excitons confined to GaAs quantum well tubes of 8 and 4 nm widths embedded into an AlGaAs barrier are seen to ionize at high bias levels. Spectroscopic signatures of the ground and excited states confined to the QWT seen in PL, PLE, and PC data are consistent with simple numerical calculations. The demonstration of good electrical contact with the QWTs enables the study of Stark effect shifts in the sharp emission lines of excitons localized to quantum dot-like states within the QWT. Atomic resolution cross-sectional TEM measurements and an analysis of the quantum confined Stark effect of these dots provide insights into the nature of the exciton localization in these nanostructures.
authors.affiliation: Department of Physics, University of Cincinnati , Cincinnati, Ohio 45221-0011, United States.
authors.forename: Bekele H
authors.initials: BH
authors.lastname: Badada
authors.affiliation: Department of Physics, University of Cincinnati , Cincinnati, Ohio 45221-0011, United States.
authors.forename: Teng
authors.initials: T
authors.lastname: Shi
authors.affiliation: Department of Physics, University of Cincinnati , Cincinnati, Ohio 45221-0011, United States.
authors.forename: Howard E
authors.initials: HE
authors.lastname: Jackson
authors.affiliation: Department of Physics, University of Cincinnati , Cincinnati, Ohio 45221-0011, United States.
authors.forename: Leigh M
authors.initials: LM
authors.lastname: Smith
authors.forename: Changlin
authors.initials: C
authors.lastname: Zheng
authors.forename: Joanne
authors.initials: J
authors.lastname: Etheridge
authors.affiliation: Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University , Canberra, ACT 2601, Australia.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Gao
authors.affiliation: Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University , Canberra, ACT 2601, Australia.
authors.forename: H Hoe
authors.initials: HH
authors.lastname: Tan
authors.affiliation: Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University , Canberra, ACT 2601, Australia.
authors.forename: Chennupati
authors.initials: C
authors.lastname: Jagadish
keywords: Nanowires; Stark effect; heterostructures; photocurrent; quantum well