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Micromechanical Testing of Silver Nanowires
The small size of specimens often imposes significant challenges for
preparation and testing. To overcome these difficulties, Prof. Horacio
Espinosa’s group at the Mechanical Engineering Department in Northwestern University, USA, has developed a microelectromechanical system that allows mechanical testing of nanowires (see left figure). The
system is capable of simultaneous four-point electrical measurements,
therefore enabling piezoresistivity and -electricity measurements [1].
In order to mount the silver nanowires, they employed an attocube
nanomanipulator, composed of three stacked ECS3030 positioners, one
for each axis of movement. The nanomanipulator is positioned inside
an SEM chamber and interfaced to the ECC100 piezo-controller outside
the chamber.
[1] R.A. Bernal, et al., Small 10, 725 (2014).
Automatic Mapping of Semiconductor Quantum Dots
Returning to interesting sample positions has never been easier: Yves
Delley from the Quantum Photonics Group (QPG) at the ETH Zurich have
– based on attocube positioners with resistive encoders – built a micro-photoluminescence (PL) setup and automated it to a great extent.
They programmed a fully automated routine for raster-imaging a full
sample of up to 4 x 4 mm² as well as implemented an auto-focus routine.
Once initiated, the positioners are moved frame-by-frame and a CCD
camera takes images of the PL of their semiconductor quantum dot samples. Knowing the coordinates of all individual images, it is easy to put
together a complete map of the sample (see figure on the left).
“Now, we have to select the interesting dots, at which we want to take
a closer look”, says Yves Delley, the responsible project researcher
at QPG and gags: “Yet, in order to find the shortest route between all
these quantum dots, we would need a quantum computer to solve this
problem.”
(Image kindly provided by Yves Delley, Quantum Photonics Group, ETH Zurich, Switzerland)
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Piezo-based Nano Drives