7 research outputs found
Polarity determination in ZnSe nanowires by HAADF STEM
High angle annular dark field scanning transmission electron microscopy is
used to analyze the polarity of ZnSe nanowires grown, by molecular beam
epitaxy, on GaAs substrates. The experimental results are compared to simulated
images in order to verify possible experimental artefacts. In this work we show
that for this type of nano-objects, a residual tilt of the specimen below 15
mrad, away from the crystallographic zone axis does not impair the
interpretation of the experimental images
Insertion of CdSe quantumdots in ZnSe nanowires : MBE growth and microstructure analysis
ZnSe nanowire growth has been successfully achieved on ZnSe (100) and (111)B
buffer layers deposited on GaAs substrates. Cubic [100] oriented ZnSe nanowires
or [0001] oriented hexagonal NWs are obtained on (100) substrates while [111]
oriented cubic mixed with [0001] oriented hexagonal regions are obtained on
(111)B substrates. Most of the NWs are perpendicular to the surface in the last
case. CdSe quantum dots were successfully incorporated in the ZnSe NWs as
demonstrated by transmission electron microscopy, energy filtered TEM and high
angle annular dark field scanning TEM measurements
Correction to Ultrafast Room Temperature Single-Photon Source from Nanowire-Quantum Dots
Correction to Ultrafast Room Temperature Single-Photon Source from Nanowire-Quantum Dots
International audienc
Ultrafast Room Temperature Single-Photon Source from Nanowire-Quantum Dots
Epitaxial semiconductor quantum dots are particularly
promising
as realistic single-photon sources for their compatibility with manufacturing
techniques and possibility to be implemented in compact devices. Here,
we demonstrate for the first time single-photon emission up to room
temperature from an epitaxial quantum dot inserted in a nanowire,
namely a CdSe slice in a ZnSe nanowire. The exciton and biexciton
lines can still be resolved at room temperature and the biexciton
turns out to be the most appropriate transition for single-photon
emission due to a large nonradiative decay of the bright exciton to
dark exciton states. With an intrinsically short radiative decay time
(≈300 ps) this system is the fastest room temperature single-photon
emitter, allowing potentially gigahertz repetition rates