Schubert, S.; Smedley, J.; Rao, T.; Ruiz-Osés, M.; Liang, X.; Ben-Zvi, I.; Padmore, H.; Vecchione, T.: XPS and UHV-AFM Analysis of the K2CsSb- Photocathodes Growth. In: Proceedings of 4th International Particle Accelerator Conference, IPAC 2013, May 13-17, 2013, Shanghai, China. , 2013. - ISBN 978-3-95450-122-9, p. 291-293
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Next generation light sources, based on Energy Recovery Linac and Free Electron Laser technology will rely on photoinjector based electron sources. Successful operation of such sources requires reliable photocathodes with long operational life, uniform and high quantum efficiency, low thermal emittance and low dark current. The goal of this project is to construct a cathode which meets these requirements. Advances in photocathode research must take a combined effort. The materials have to be analyzed by means of chemical composition, surface structure and these findings have to be correlated to the quantum efficiency and performance in the injector. The presented work focuses on the chemical composition and surface structure of K2CsSb photocathodes. The XPS and AFM measurements were performed at the Center of Functional Nanomaterials at BNL. K2CsSb photocathodes were grown under UHV conditions. The components were adsorbed one at a time and after each growth step the corresponding XPS spectra was taken. During growth the quantum efficiency was recorded. As last step the sample was moved into the AFM without exposure to air to determine the surface roughness.