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https://doi.org/10.18429/JACoW-IPAC2014-MOPRI038
Title Study on Quantum Efficiency of NEA-GaAs with Various Thermal Treatments; The Increase in Quantum Efficiency by the Low Temperature Treatment.
Authors
  • K. Hayase, R. Chiba, H. Iijima, Y. Inagaki, T. Meguro
    Tokyo University of Science, Tokyo, Japan
Abstract Negative electron affinity (NEA) surface are formed by deposition of Cs atoms on p-GaAs, and the drastic increase in the electron emission is observed by the Yo-Yo method. It is necessary to remove oxide layers of GaAs surface for the NEA surface formation, therefore the thermal treatment was carried out prior to the NEA activation. We have discussed the quantum efficiency (QE) with different thermal history. GaAs surfaces cleaned with organic solvents were thermally treated with the temperature sequence of 773K, 823K, and 723K. The NEA activation was carried out at every temperature. The QE less than 1% was obtained with 773K of treatment temperature on the initial surface. Then the QE increased at 10% after treatment at higher 823K. Successive increase of the QE to 13% was observed with a reduced temperature treatment at 723K. The GaAs surfaces after the thermal treatment in the high temperature region with the NEA activation are different from the as-cleaned-GaAs surfaces probably in stoichiometry or morphology due to desorption of As and Ga atoms. The role of thermal treatment with NEA activation is the modification of surface properties important for elevating the QE.
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Conference IPAC2014, Dresden, Germany
Series International Particle Accelerator Conference (5th)
Proceedings Link to full IPAC2014 Proccedings
Session Poster Session, Ribery Area
Date 16-Jun-14   16:00–18:00
Main Classification 03 Particle Sources and Alternative Acceleration Techniques
Sub Classification T02 Electron Sources
Keywords electron, ion, site, experiment, vacuum
Publisher JACoW Publishing, Geneva, Switzerland
Editors Christine Petit-Jean-Genaz (CERN, Geneva, Switzerland); Gianluigi Arduini (CERN, Geneva, Switzerland); Peter Michel (HZDR, Dresden, Germany); Volker RW Schaa (GSI, Darmstadt, Germany)
ISBN 978-3-95450-132-8
Published July 2014
Copyright
Copyright © 2014 by JACoW, Geneva, Switzerland     CC-BY Creative Commons License
cc Creative Commons Attribution 3.0