Tracing the valence band maximum during epitaxial growth of HfS2 on WSe2

Applying angle resolved photoemission and scanning tunneling microscopy (ST M) during different stages of epitaxial growth of HfS2 on WSe2 allows an ev aluation of the electronic valence band spectra as a function of position z perpendicular to the interface. In combination with photon energy dependen t photoemission measurements of clean WSe2 and HfS2 samples, mapping k(perp endicular to) dispersions of valence bands' reliable values for the valence band maxima (VBM) have been obtained. Upon different stages of growth, the valence band maximum can thus be traced during the build up of the interfa ce giving an accurate value for the valence band offset of this heterojunct ion. (C) 2000 Elsevier Science B.V. All rights reserved.