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TY - CONF AU - Saha, P. AU - Echeverria, E. AU - Galdi, A. AU - Karkare, S.S. AU - Maxson, J.M. AU - Montgomery, E.J. AU - Pennington, C.A. AU - Poddar, S. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Epitaxial Alkali-Antimonide Photocathodes on Lattice-matched Substrates J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - Alkali-antimonides photocathodes, characterized by high quantum efficiency (QE) and low mean transverse energy (MTE) in the visible range of spectrum, are excellent candidates for electron sources to drive X-ray Free Electron Lasers (XFEL) and Ultrafast Electron Diffraction (UED). A key figure of merit for these applications is the electron beam brightness, which is inversely proportional to MTE. MTE can be limited by nanoscale surface roughness. Recently, we have demonstrated physically and chemically smooth Cs₃Sb cathodes on Strontium Titanate (STO) substrates grown via co-deposition technique. Such flat cathodes could result from a more ordered growth. In this paper, we present RHEED data of co-deposited Cs₃Sb cathodes on STO. Efforts to achieve epitaxial growth of Cs₃Sb on STO are then demonstrated via RHEED. We find that films grown epitaxially on substrates like STO and SiC (previously used to achieve single crystalline Cs₃Sb) exhibit QE higher than the polycrystalline Cs₃Sb cathodes, by an order of magnitude below photoemission threshold. Given the larger QE, lower laser fluence could be used to extract high charge densities, thereby leading to enhanced beam brightness. PB - JACoW Publishing CP - Geneva, Switzerland SP - 289 EP - 291 KW - cathode KW - ECR KW - electron KW - laser KW - lattice DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUYD5 UR - https://jacow.org/napac2022/papers/tuyd5.pdf ER -