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TY - CONF AU - Hayase, K. AU - Chiba, R. AU - Iijima, H. AU - Inagaki, Y. AU - Meguro, T. ED - Petit-Jean-Genaz, Christine ED - Arduini, Gianluigi ED - Michel, Peter ED - Schaa, Volker RW TI - Study on Quantum Efficiency of NEA-GaAs with Various Thermal Treatments; The Increase in Quantum Efficiency by the Low Temperature Treatment. J2 - Proc. of IPAC2014, Dresden, Germany, June 15-20, 2014 C1 - Dresden, Germany T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - 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. PB - JACoW CP - Geneva, Switzerland SP - 682 EP - 684 KW - electron KW - ion KW - site KW - experiment KW - vacuum DA - 2014/07 PY - 2014 SN - 978-3-95450-132-8 DO - 10.18429/JACoW-IPAC2014-MOPRI038 UR - http://jacow.org/ipac2014/papers/mopri038.pdf ER -