Evans-Lutterodt, Kenneth
Cesium telluride photocathodes: PLD assisted epitaxial growth
Photocathodes are fundamental to the advancement of electron accelerators and photon detectors. While ultrasmooth photocathodes produced by co-deposition processes have been developed, their beam brightness remains limited by surface and bulk disorders inherent to polycrystalline structures. Epitaxial growth offers a transformative pathway to address these challenges, enabling the production of high-brightness electron beams. This work reports the pulsed laser deposition (PLD) assisted epitaxial growth of Cs2Te photocathodes on lattice-matched single-crystal substrates. Real-time growth monitoring via X-ray fluorescence (XRF) confirmed stoichiometric composition, while growth oscillations provided insights into the deposition process. The epitaxial nature of the films, characterized by a flat surface and high crystallinity, is validated through reflection high-energy electron diffraction (RHEED). Bulk crystallinity was further studied through X-ray diffraction (XRD) analysis. Spectral response of quantum efficiency (QE) with wavelength range 200 nm to 400 nm has been reported