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Size shift of XPS lines observed from PbS nanocrystals
Author(s) -
Kovalev Anatoly I.,
Wainstein Dmitry L.,
Rashkovskiy Alexandr Yu.,
Osherov Anna,
Golan Yuval
Publication year - 2010
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.3243
Subject(s) - x ray photoelectron spectroscopy , nanocrystal , band gap , blueshift , analytical chemistry (journal) , materials science , binding energy , spectroscopy , chemical bath deposition , chemistry , nanotechnology , photoluminescence , atomic physics , optoelectronics , nuclear magnetic resonance , physics , chromatography , quantum mechanics
Crystals of PbS with different sizes were obtained by chemical deposition from aqueous solution (chemical bath deposition technique) onto undoped Si (100) substrate. The morphology and size of crystals were analyzed by high resolution scanning electron microscopy. The fine structure of Pb 4f and S 2p photoelectron lines was measured by X‐ray photoelectron spectroscopy with monochromatic Al Kα source ( h ν = 1486.6 eV). The phenomenon of size shift, i.e. growth of binding energies for both donor Pb 4f and acceptor S 2p photoelectron lines with decreasing nanocrystals' size, was found and quantified as a function of nanocrystals' size. The size shift values of the Pb 4f 5/2 and 4f 7/2 lines were determined for nanocrystals with a size from 20 to 250 nm. The interband and intraband electronic transitions were investigated by high resolution electron energy losses spectroscopy. It was shown that width and spatial anisotropy of the band gap depend on the size of PbS nanocrystals. The dependence of size shift from nanocrystals' size, the nature of this phenomenon, and a role of changes in fine structure of electronic states near the band gap are discussed in the report. Copyright © 2010 John Wiley & Sons, Ltd.