Valency of Yb in PbS and PbTe Determined by XPS |
| Z. Gołacki Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland and M. Heinonen Department of Applied Physics, University of Turku, ElectroCity, Tykistokatu 2D, 20520 Turku, Finland |
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| X-ray photoelectron spectroscopy experiments on PbTe:Yb, PbS:Yb, PbTe, and PbS crystals have been performed using the monochromatized Al Kα radiation. The valence band spectrum of PbTe:Yb exhibits one set of peaks associated with divalent Yb initial states, but two sets associated with divalent and trivalent Yb are observed for PbS:Yb. The valency of Yb in PbTe:Yb is 2 (within an accuracy of the experiment) but in PbS:Yb the mixed valency of Yb is seen. These conclusions are confirmed by an analysis of Yb 4d spectra in PbTe:Yb and PbS:Yb crystals. |
| DOI: 10.12693/APhysPolA.91.775 PACS numbers: 71.20.Nr, 79.60.-i |