Chinese Academy of Sciences, Lanzhou (China); Univ. of Chinese Academy of Sciences, Beijing (China); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
SVT Assoc., Inc., Eden Prairie, MN (United States)
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Photocathodes that provide high polarization and high quantum efficiency (QE) can significantly enhance the physics capabilities of electron accelerators. We report record-level QE from a high-polarization strained GaAs/GaAsP superlattice photocathode fabricated with a Distributed Bragg Reflector (DBR). The DBR photocathode technique enhances the absorption of incident laser light thereby enhancing QE, but as literature suggests, it is very challenging to optimize all of the parameters associated with the fabrication of complicated photocathode structures composed of many distinct layers. Past reports of DBR photocathodes describe high polarization but typically QE of only ~ 1%, which is comparable to QE of high polarization photocathodes grown without a DBR structure. As a result, this work describes a new strained GaAs/GaAsP superlattice DBR photocathode exhibiting polarization of 84% and QE of 6.4%.
@article{osti_1343296,
author = {Liu, Wei and Chen, Yiqiao and Lu, Wentao and Moy, Aaron and Poelker, Matthew and Stutzman, Marcy and Zhang, Shukui},
title = {Record-level quantum efficiency from a high polarization strained GaAs/GaAsP superlattice photocathode with distributed Bragg reflector},
annote = {Photocathodes that provide high polarization and high quantum efficiency (QE) can significantly enhance the physics capabilities of electron accelerators. We report record-level QE from a high-polarization strained GaAs/GaAsP superlattice photocathode fabricated with a Distributed Bragg Reflector (DBR). The DBR photocathode technique enhances the absorption of incident laser light thereby enhancing QE, but as literature suggests, it is very challenging to optimize all of the parameters associated with the fabrication of complicated photocathode structures composed of many distinct layers. Past reports of DBR photocathodes describe high polarization but typically QE of only ~ 1%, which is comparable to QE of high polarization photocathodes grown without a DBR structure. As a result, this work describes a new strained GaAs/GaAsP superlattice DBR photocathode exhibiting polarization of 84% and QE of 6.4%.},
doi = {10.1063/1.4972180},
url = {https://www.osti.gov/biblio/1343296},
journal = {Applied Physics Letters},
issn = {ISSN APPLAB},
number = {25},
volume = {109},
place = {United States},
publisher = {American Institute of Physics (AIP)},
year = {2016},
month = {12}}
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