Laterally resolved measurements of polycrystalline cesium iodide surfaces

Abstract

Laterally resolved measurements of polycrystalline cesium iodide surfaces Rudolf, Petra; Marchal, F.; Sporken, R.; Caudano, R.; dellOrto, T.; Almeida, J.; Braem, A.; Piuz, F.; Sgobba, S.; Paic, G. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractThe aim of this work was to establish the correlation between the local chemical composition and morphology of polycrystalline cesium iodide (CsI) and its local quantum efficiency. We used a laterally resolved Electron Spectroscopy for Chemical Analysis (ESCA-300) apparatus and a Scanning Auger Microprobe (SAM) to investigate the lateral inhomogeneity of the CsI surface stoichiometry.The local quantum efficiency (QE) was determined by measuring the secondary electron emission in Photoemission Electron Microscopy both with a non-monochromatized deuterium lamp and with tunable X-ray synchrotron radiation as the excitation source. CsI films on different substrates were studied. We found that the local QE depends strongly on the morphology, on the local stoichiometry and on carbon contamination. The results allow for an optimisation of the quantum efficiency of large area photocathodes.

Structural characterization of “as-deposited” cesium iodide films studied by X-ray diffraction and transmission electron microscopy techniques

“…However, it has been observed that the thermal evaporation is the best choice forming a stoichiometric Cs:I ratio [21] as well as the highest absolute quantum efficiency (QE) compared to other preparation techniques [17][18][19][20]. Even with its enormous applications in a variety of fields discussed above, very few of the earlier studies in this field deal with characterization of CsI film structure [22][23][24][25][26][27]. X-ray diffraction (XRD) and transmission electron microscopy (TEM) are the two important techniques which are commonly used for the structural characterization.…”