Electronic structure of designed [(SnSe)1+δ]m[TiSe2]2 heterostructure thin films with tunable layering sequence. Issue 12 (28th June 2019)

• Record Type: Journal Article
• Authors: Göhler, Fabian; Hamann, Danielle M.; Rösch, Niels; Wolff, Susanne; Logan, Jacob T.; Fischer, Robert; Speck, Florian; Johnson, David C.; Seyller, Thomas
• Is Part Of: Journal of materials research. Volume 34:Issue 12(2019)
• Page Start: 1965
• Page End: 1975
• Publication Date: 2019-06-28
• Subjects: electronic structure, -- nanostructure, -- X-ray photoelectron spectroscopy (XPS); Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1557/jmr.2019.128
• Languages: English
• ISSNs: 0884-2914

Abstract

Abstract: Abstract : A series of ${\left\hbox[ {{{\left\hbox( {{\rm{SnSe}}} \right\hbox)}_{1 \hbox+ \delta }}} \right\hbox]_m}{\left\hbox[ {{\rm{TiS}}{{\rm{e}}_2}} \right\hbox]_2}$ heterostructure thin films built up from repeating units of m bilayers of SnSe and two layers of TiSe2 were synthesized from designed precursors. The electronic structure of the films was investigated using X-ray photoelectron spectroscopy for samples with m = 1, 2, 3, and 7 and compared to binary samples of TiSe2 and SnSe. The observed binding energies of core levels and valence bands of the heterostructures are largely independent of m . For the SnSe layers, we can observe a rigid band shift in the heterostructures compared to the binary, which can be explained by electron transfer from SnSe to TiSe2 . The electronic structure of the TiSe2 layers shows a more complicated behavior, as a small shift can be observed in the valence band and Se3 d spectra, but the Ti2 p core level remains at a constant energy. Complementary UV photoemission spectroscopy measurements confirm a charge transfer mechanism where the SnSe layers donate electrons into empty Ti3 d states at the Fermi energy.