BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-3404
DTSTART:20140904T150000Z
DURATION:PT1H0M0S
DTSTAMP:20260419T161344Z
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.<br>
\n<br>
\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.<br>
\n<br>
\n <br>
\n<br>
\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.<br>
\n<br>
\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
END:VEVENT
END:VCALENDAR