Cargando…

Ultrafast electron imaging of surface charge carrier dynamics at low voltage

The performance of optoelectronic devices strongly depends on charge carrier dynamics on top of surfaces of the absorber layers. Unfortunately, this information cannot be selectively probed using conventional ultrafast laser spectroscopic methods, due to the large penetration depth (tens of nm to μm...

Descripción completa

Detalles Bibliográficos
Autores principales: Zhao, Jianfeng, Bakr, Osman M., Mohammed, Omar F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Crystallographic Association 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7105398/
https://www.ncbi.nlm.nih.gov/pubmed/32266302
http://dx.doi.org/10.1063/4.0000007
_version_ 1783512391668989952
author Zhao, Jianfeng
Bakr, Osman M.
Mohammed, Omar F.
author_facet Zhao, Jianfeng
Bakr, Osman M.
Mohammed, Omar F.
author_sort Zhao, Jianfeng
collection PubMed
description The performance of optoelectronic devices strongly depends on charge carrier dynamics on top of surfaces of the absorber layers. Unfortunately, this information cannot be selectively probed using conventional ultrafast laser spectroscopic methods, due to the large penetration depth (tens of nm to μm) of the photon pulses in the pump-probe configurations. Therefore, ultrafast time-resolved approaches that can directly and selectively visualize the behavior of the surface carrier dynamics are urgently needed. Here, we introduce a novel methodology of low-voltage scanning ultrafast electron microscopy that can take ultrafast time-resolved images (snapshots) of the surface of materials at the sub-nanometer level. By this approach, the surface of the photoactive materials is optically excited and imaged, using a pulsed low-voltage electron beam (1 keV) that interacts with the surface to generate secondary electrons with an energy of a few eV, and that are emitted only from the top surface of materials, providing direct information about the carrier dynamics and the localization of electron/holes in real space and time. An outlook on the potential applications of this low voltage approach in different disciplines will also be discussed.
format Online
Article
Text
id pubmed-7105398
institution National Center for Biotechnology Information
language English
publishDate 2020
publisher American Crystallographic Association
record_format MEDLINE/PubMed
spelling pubmed-71053982020-04-07 Ultrafast electron imaging of surface charge carrier dynamics at low voltage Zhao, Jianfeng Bakr, Osman M. Mohammed, Omar F. Struct Dyn Perspectives (Contributed) The performance of optoelectronic devices strongly depends on charge carrier dynamics on top of surfaces of the absorber layers. Unfortunately, this information cannot be selectively probed using conventional ultrafast laser spectroscopic methods, due to the large penetration depth (tens of nm to μm) of the photon pulses in the pump-probe configurations. Therefore, ultrafast time-resolved approaches that can directly and selectively visualize the behavior of the surface carrier dynamics are urgently needed. Here, we introduce a novel methodology of low-voltage scanning ultrafast electron microscopy that can take ultrafast time-resolved images (snapshots) of the surface of materials at the sub-nanometer level. By this approach, the surface of the photoactive materials is optically excited and imaged, using a pulsed low-voltage electron beam (1 keV) that interacts with the surface to generate secondary electrons with an energy of a few eV, and that are emitted only from the top surface of materials, providing direct information about the carrier dynamics and the localization of electron/holes in real space and time. An outlook on the potential applications of this low voltage approach in different disciplines will also be discussed. American Crystallographic Association 2020-03-30 /pmc/articles/PMC7105398/ /pubmed/32266302 http://dx.doi.org/10.1063/4.0000007 Text en © 2020 Author(s). 2329-7778/2020/7(2)/021001/7 All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Perspectives (Contributed)
Zhao, Jianfeng
Bakr, Osman M.
Mohammed, Omar F.
Ultrafast electron imaging of surface charge carrier dynamics at low voltage
title Ultrafast electron imaging of surface charge carrier dynamics at low voltage
title_full Ultrafast electron imaging of surface charge carrier dynamics at low voltage
title_fullStr Ultrafast electron imaging of surface charge carrier dynamics at low voltage
title_full_unstemmed Ultrafast electron imaging of surface charge carrier dynamics at low voltage
title_short Ultrafast electron imaging of surface charge carrier dynamics at low voltage
title_sort ultrafast electron imaging of surface charge carrier dynamics at low voltage
topic Perspectives (Contributed)
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7105398/
https://www.ncbi.nlm.nih.gov/pubmed/32266302
http://dx.doi.org/10.1063/4.0000007
work_keys_str_mv AT zhaojianfeng ultrafastelectronimagingofsurfacechargecarrierdynamicsatlowvoltage
AT bakrosmanm ultrafastelectronimagingofsurfacechargecarrierdynamicsatlowvoltage
AT mohammedomarf ultrafastelectronimagingofsurfacechargecarrierdynamicsatlowvoltage