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UID:UW-Physics-Event-3404
DTSTART:20140904T150000Z
DURATION:PT1H0M0S
DTSTAMP:20240319T133504Z
LAST-MODIFIED:20140827T153446Z
LOCATION:5310 Chamberlin Hall
SUMMARY:Multiplexing of Nanostructure Devices\, R. G. Herb Condensed M
atter Seminar\, Dr. Luke Smith\, University of Cambridge
DESCRIPTION:It is highly desirable to increase the number of nanostruc
ture devices on a single low temperature semiconductor chip for high t
hrough-put testing\, and for creation of integrated quantum devices. W
e have developed an on-chip multiplexing technique which significantly
increases the number of devices that can be measured during a single
cooldown in a cryostat. This was used to address an array of 256 split
gates on a GaAs/AlGaAs heterostructure\; the largest number of such d
evices on an individual chip to date.
\n
\nA rich variety of p
hysical phenomena can be investigated using the split gate\, despite t
he simple device geometry. Electron-electron interaction effects manif
est in the formation of an anomalous conductance feature known as the
‘0.7 structure’\, the specific origin of which is currently debate
d. We have performed a detailed statistical analysis of this structure
using arrays of identical devices\, as well as arrays in which the ge
ometry of the split gates vary. Our results link this structure to sma
ll variations in the specific confining potential within individual de
vices.
\n
\n
\n
\nAside from exploring fundamental ph
ysics\, the multiplexer can also be used to perform important tests of
the suitability of nanostructure devices as elements for nanoelectron
ic or quantum computing architectures. We have performed yield studies
\, and investigated the reproducibility of device characteristics on r
epeated cooldowns. Additionally we have presented a technique which ca
n be used to assess the homogeneity of the semiconducting substrate it
self.
\n
\nThe multiplexing scheme is versatile and recently a
charge-locking technique has been developed to sequentially bias a la
rge number of gates\, in order to form complex device structures. Init
ial studies have shown that this can be used to contact an array of qu
antum dots. Multiplexing is a powerful tool which both increases the e
fficiency of research and presents a new approach to measurements in t
his field.
URL:https://www.physics.wisc.edu/events/?id=3404
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