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URLhttps://doi.org/10.18429/JACoW-NAPAC2025-WEP055
TitleLight-induced enhancement of quantum efficiency in III-nitride photocathodes
Authors
  • M. Moeini Rizi, S. Karkare, A. Ullattuparambil
    Arizona State University
  • P. Saha, L. Lathpandura, L. Cultrera
    Brookhaven National Laboratory
  • S. Shahedipour-Sandvik, A. Lanjani
    University at Albany, State University of New York
AbstractHigh quantum efficiency (QE) semiconductor photocathodes are essential for generating high average beam current and brightness. One class of semiconductor photocathodes considered for use in photoinjectors for unpolarized and polarized electron beams are III-nitride heterostructures. These materials can exhibit negative electron affinity at the surface, utilizing intrinsic polarization fields to engineer the band structure without the need for additional surface treatments. In this study, we investigate the effects of light exposure on the surface of III-nitride photocathodes and the resulting changes in QE and photoemission, using photoemission electron microscopy (PEEM) for characterization. We demonstrate that exposing a GaN photocathode to a 240 nm wavelength laser at 870 µW for 15 minutes increases the QE by two orders of magnitude, with a maximum QE of 2.34 × 10⁻⁴ observed. Although III-nitride photocathodes are known for their robustness, our findings indicate that laser exposure can significantly alter their QE. Our observations reveal the need for a detailed investigation of photo-induced effects on QE in III-Nitride photocathodes.
Paperdownload: WEP055.pdf
CiteBibTeX, LaTeX, Text/Word, RIS, EndNote
Conference6th North American Particle Accel. Conf. (NAPAC2025)
Series
LocationSacramento, CA, USA
Date10-15 Aug 2025
PublisherJACoW Publishing, Geneva, Switzerland
Editorial BoardTor O. Raubenheimer (SLAC), Roark A. Marsh (LLNL), Eric Prebys (UC Davis), Ling Wang (MSU), Petr M. Anisimov (LANL), Kip Bishofberger (LANL), Gustavo Bruno (ANL), Zhichu Chen (SARI), Jan Chrin (PSI), Kelly Jaje (ANL), Jaeyu Lee (POSTECH), Magdalena Montes-Loera (SLAC), Mary Saethre (PHENOTYPE), Tasha Summers (SLAC), Kent Wootton (ANL)
Online ISBN978-3-95450-261-5
Online ISSN2673-7000
Received08 August 2025
Revised14 August 2025
Accepted15 August 2025
Issued28 January 2026
DOI10.18429/JACoW-NAPAC2025-WEP055
Pages786-788