Real-Space Imaging of Carrier Dynamics of Materials Surfaces by Second-Generation Four-Dimensional Scanning Ultrafast Electron Microscopy

Handle URI:
http://hdl.handle.net/10754/578971
Title:
Real-Space Imaging of Carrier Dynamics of Materials Surfaces by Second-Generation Four-Dimensional Scanning Ultrafast Electron Microscopy
Authors:
Sun, Jingya; Melnikov, Vasily; Khan, Jafar Iqbal; Mohammed, Omar F. ( 0000-0001-8500-1130 )
Abstract:
In the fields of photocatalysis and photovoltaics, ultrafast dynamical processes, including carrier trapping and recombination on material surfaces, are among the key factors that determine the overall energy conversion efficiency. A precise knowledge of these dynamical events on the nanometer (nm) and femtosecond (fs) scales was not accessible until recently. The only way to access such fundamental processes fully is to map the surface dynamics selectively in real space and time. In this study, we establish a second generation of four-dimensional scanning ultrafast electron microscopy (4D S-UEM) and demonstrate the ability to record time-resolved images (snapshots) of material surfaces with 650 fs and ∼5 nm temporal and spatial resolutions, respectively. In this method, the surface of a specimen is excited by a clocking optical pulse and imaged using a pulsed primary electron beam as a probe pulse, generating secondary electrons (SEs), which are emitted from the surface of the specimen in a manner that is sensitive to the local electron/hole density. This method provides direct and controllable information regarding surface dynamics. We clearly demonstrate how the surface morphology, grains, defects, and nanostructured features can significantly impact the overall dynamical processes on the surface of photoactive-materials. In addition, the ability to access two regimes of dynamical probing in a single experiment and the energy loss of SEs in semiconductor-nanoscale materials will also be discussed.
KAUST Department:
Solar and Photovoltaic Engineering Research Center (SPERC); Physical Sciences and Engineering (PSE) Division
Citation:
Real-Space Imaging of Carrier Dynamics of Materials Surfaces by Second-Generation Four-Dimensional Scanning Ultrafast Electron Microscopy 2015, 6 (19):3884 The Journal of Physical Chemistry Letters
Publisher:
American Chemical Society (ACS)
Journal:
The Journal of Physical Chemistry Letters
Issue Date:
14-Sep-2015
DOI:
10.1021/acs.jpclett.5b01867
Type:
Article
ISSN:
1948-7185
Additional Links:
http://pubs.acs.org/doi/10.1021/acs.jpclett.5b01867
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Solar and Photovoltaic Engineering Research Center (SPERC)

Full metadata record

DC FieldValue Language
dc.contributor.authorSun, Jingyaen
dc.contributor.authorMelnikov, Vasilyen
dc.contributor.authorKhan, Jafar Iqbalen
dc.contributor.authorMohammed, Omar F.en
dc.date.accessioned2015-10-01T06:47:07Zen
dc.date.available2015-10-01T06:47:07Zen
dc.date.issued2015-09-14en
dc.identifier.citationReal-Space Imaging of Carrier Dynamics of Materials Surfaces by Second-Generation Four-Dimensional Scanning Ultrafast Electron Microscopy 2015, 6 (19):3884 The Journal of Physical Chemistry Lettersen
dc.identifier.issn1948-7185en
dc.identifier.doi10.1021/acs.jpclett.5b01867en
dc.identifier.urihttp://hdl.handle.net/10754/578971en
dc.description.abstractIn the fields of photocatalysis and photovoltaics, ultrafast dynamical processes, including carrier trapping and recombination on material surfaces, are among the key factors that determine the overall energy conversion efficiency. A precise knowledge of these dynamical events on the nanometer (nm) and femtosecond (fs) scales was not accessible until recently. The only way to access such fundamental processes fully is to map the surface dynamics selectively in real space and time. In this study, we establish a second generation of four-dimensional scanning ultrafast electron microscopy (4D S-UEM) and demonstrate the ability to record time-resolved images (snapshots) of material surfaces with 650 fs and ∼5 nm temporal and spatial resolutions, respectively. In this method, the surface of a specimen is excited by a clocking optical pulse and imaged using a pulsed primary electron beam as a probe pulse, generating secondary electrons (SEs), which are emitted from the surface of the specimen in a manner that is sensitive to the local electron/hole density. This method provides direct and controllable information regarding surface dynamics. We clearly demonstrate how the surface morphology, grains, defects, and nanostructured features can significantly impact the overall dynamical processes on the surface of photoactive-materials. In addition, the ability to access two regimes of dynamical probing in a single experiment and the energy loss of SEs in semiconductor-nanoscale materials will also be discussed.en
dc.language.isoenen
dc.publisherAmerican Chemical Society (ACS)en
dc.relation.urlhttp://pubs.acs.org/doi/10.1021/acs.jpclett.5b01867en
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/10.1021/acs.jpclett.5b01867.en
dc.subjectultrafast electron microscopyen
dc.subjectsurface dynamicsen
dc.subjectenergy lossen
dc.subjectelectron impact dynamicsen
dc.subjectphoton impact dynamicsen
dc.titleReal-Space Imaging of Carrier Dynamics of Materials Surfaces by Second-Generation Four-Dimensional Scanning Ultrafast Electron Microscopyen
dc.typeArticleen
dc.contributor.departmentSolar and Photovoltaic Engineering Research Center (SPERC)en
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalThe Journal of Physical Chemistry Lettersen
dc.eprint.versionPost-printen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorSun, Jingyaen
kaust.authorMelnikov, Vasilyen
kaust.authorKhan, Jafar Iqbalen
kaust.authorMohammed, Omar F.en
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