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dc.contributor.authorBhandari, Sagar
dc.contributor.authorWestervelt, Robert M.
dc.date.accessioned2017-10-03T20:16:01Z
dc.date.issued2017
dc.identifier.citationBhandari, Sagar, and Robert M Westervelt. 2017. “Imaging Electron Motion in Graphene.” Semiconductor Science and Technology 32 (2) (January 5): 024001. doi:10.1088/1361-6641/32/2/024001.en_US
dc.identifier.issn0268-1242en_US
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:33980572
dc.description.abstractA cooled scanning probe microscope (SPM) is an ideal tool to image electronic motion in graphene: the SPM tip acts as a scanning gate, which interacts with the electron gas below. We introduce the technique using our group's previous work on imaging electron flow from a quantum point contact in a GaAs 2DEG and tuning an InAs quantum dot in an InAs/InP nanowire. Carriers in graphene have very different characteristics: electrons and holes travel at a constant speed with no bandgap, and they pass through potential barriers via Klein tunneling. In this paper, we review the extension of SPM imaging techniques to graphene. We image the cyclotron orbits passing between two narrow contacts in a single-atomic-layer graphene device in a perpendicular magnetic field. Magnetic focusing produces a peak in transmission between the contacts when the cyclotron diameter is equal to the contact spacing. The charged SPM tip deflects electrons passing from one contact to the other, changing the transmission when it interrupts the flow. By displaying the change in transmission as the tip is raster scanned above the sample, an image of flow is obtained. In addition, we have developed a complementary technique to image electronic charge using a cooled scanning capacitance microscope (SCM) that uses a sensitive charge preamplifier near the SPM tip to achieve a charge noise level 0.13 e Hz−1/2 with high spatial resolution 100 nm. The cooled SPM and SCM can be used to probe the motion of electrons on the nanoscale in graphene devices.en_US
dc.description.sponsorshipPhysicsen_US
dc.language.isoen_USen_US
dc.publisherIOP Publishingen_US
dc.relation.isversionofdoi:10.1088/1361-6641/32/2/024001en_US
dash.licenseLAA
dc.titleImaging electron motion in grapheneen_US
dc.typeJournal Articleen_US
dc.description.versionVersion of Recorden_US
dc.relation.journalSemiconductor Science and Technologyen_US
dash.depositing.authorWestervelt, Robert M.
dc.date.available2017-10-03T20:16:01Z
dc.identifier.doi10.1088/1361-6641/32/2/024001*
workflow.legacycommentsFAR2016en_US
dash.contributor.affiliatedBhandari, Sagar
dash.contributor.affiliatedWestervelt, Robert


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