Characterization of oxides of cesium

Cesium oxides are materials of great interest to the photodetection industry because of their relatively low work function (similar to1 eV). Used mainly as coating films for photoemissive devices, they provide high wavelength thresholds and high photocurrents. However, they are unstable, air-sensitive, and hygroscopic, rendering them short-lived and limiting their applications. Although the technology of these devices is highly developed, their characterization on the micro- and nanoscale suffers from their poor chemical stability and poor crystallinity. In the present study, cesium oxides were synthesized from the elements and were characterized using a combination of chemical and structural analysis techniques. Because the reaction products were extremely sensitive to humidity, sample analysis without atmospheric exposure was essential, and techniques were developed for the transfer of the samples to the measurements systems. Extensive data obtained from X-ray energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), X-ray diffraction (XRD), and Raman microscopy were obtained. Raman spectra with bands at 103, 742, and 1134 cm(-1) strongly confirmed the presence of the oxide, peroxide, and superoxide ions, respectively, as well as the absence of carbonate as an impurity. The A(1g) mode Of Cs2O was detected as an anti-Stokes band at 103 cm(-1). This study provides further insight into the reactivity of the various cesium oxides.