32 research outputs found
Dynamic Acoustic Control of Individual Optically Active Quantum Dot-like Emission Centers in Heterostructure Nanowires
We probe and control the optical properties of emission centers forming in
radial het- erostructure GaAs-Al0.3Ga0.7As nanowires and show that these
emitters, located in Al0.3Ga0.7As layers, can exhibit quantum-dot like
characteristics. We employ a radio frequency surface acoustic wave to
dynamically control their emission energy and occupancy state on a nanosec- ond
timescale. In the spectral oscillations we identify unambiguous signatures
arising from both the mechanical and electrical component of the surface
acoustic wave. In addition, differ- ent emission lines of a single quantum dot
exhibit pronounced anti-correlated intensity oscilla- tions during the acoustic
cycle. These arise from a dynamically triggered carrier extraction out of the
quantum dot to a continuum in the radial heterostructure. Using finite element
modeling and Wentzel-Kramers-Brillouin theory we identify quantum tunneling as
the underlying mech- anism. These simulation results quantitatively reproduce
the observed switching and show that in our systems these quantum dots are
spatially separated from the continuum by > 10.5 nm.Comment: This document is the unedited Author's version of a Submitted Work
that was subsequently accepted for publication in Nano Letters, copyright
\c{copyright} American Chemical Society after peer review. To access the
final edited and published work see
http://pubs.acs.org/doi/abs/10.1021/nl404043