SnO by XPS

Tin and various tin compounds have wide utility in coatings, electronics, and catalysts, as well as having numerous biological applications. Distinguishing between different tin compounds on surfaces is an important aspect of research in many of these disciplines. In this work, x-ray photoelectron spectroscopy has been used to obtain comparison spectra of a SnO powder. The SnO powder was generated by grinding ~150 μm granules of SnO in a mortar and pestle. Grinding is necessary because surface oxidation of the SnO granules occurs producing a SnO2 shell. It has been shown that differences in the valence band spectra provide the most direct method of distinguishing between SnO2 and SnO see J-M. Themlin, M. Chtaib, L. Henrard, P. Lambin, J. Darville, and J-M. Gilles, Phys. Rev. B 46, 2460 (1992); P. M. A. Sherwood, ibid. 41, 10151 (1990); and C. L. Lau and G. K. Wertheim, J. Vac. Sci. Technol. 15, 622 (1978). The separation between the Sn 4d core level line and the most intense Sn valence peak is also characteristic of Sn oxides see J-M. Themlin, M. Chtaib, L. Henrard, P. Lambin, J. Darville, and J-M. Gilles, Phys. Rev. B 46, 2460 (1992) and P. M. A. Sherwood, ibid. 41, 10151 (1990). In the present study, identification of the powder as SnO after grinding was verified by comparison of the measured XPS valence band spectrum with published spectra J-M. Themlin, M. Chtaib, L. Henrard, P. Lambin, J. Darville, and J-M. Gilles, Phys. Rev. B 46, 2460 (1992) and C. L. Lau and G. K. Wertheim, J. Vac. Sci. Technol. 15, 622 (1978) and by the XPS Sn:O atomic ratio. The valence band–Sn 4d separation is also consistent with that determined for SnO see J-M. Themlin, M. Chtaib, L. Henrard, P. Lambin, J. Darville, and J-M. Gilles, Phys. Rev. B 46, 2460 (1992). Core level, valence band and x-ray excited Auger spectra for the SnO powder are presented. Data were obtained with a Perkin-Elmer Physical Electronics model 5600 photoelectron spectrometer using monochromatic radiation.