Nanoscale Work Function Contrast Induced by Decanethiol Self-Assembled Monolayers on Au(111)

TSVETANOVA, MARTINA; OLDENKOTTE, VALENT J. S.; BERTOLINO, M. CANDELARIA; GAO, YUQIANG; SIEKMAN, MARTIN H.; HUSKENS, JURRIAAN; ZANDVLIET, HAROLD J. W.; SOTTHEWES, KAI

LANGMUIR

AMER CHEMICAL SOC

Lugar: Washington, D. C.; Año: 2020 vol. 36 p. 12745 - 12745

0743-7463

n this paper, we obtain maps of the spatial tunnel barrier variations in self-assembled monolayers of organosulfurs on Au(111). Maps down to the sub-nanometer scale are obtained by combining topographic scanning tunneling microscopy images with dI/dz spectroscopy. The square root of the tunnel barrier height is directly proportional to the local work function and the dI/dz signal. We use ratios of the tunnel barriers to study the work function contrast in various decanethiol phases: the lying-down striped β phase, the dense standing-up φ phase, and the oxidized decanesulfonate λ phase. We compare the induced work function variations too: the work function contrast induced by a lying-down striped phase in comparison to the modulation induced by the standing-up φ phase, as well as the oxidized λ phase. By performing these comparisons, we can account for the similarities and differences in the effects of the mechanisms acting on the surface and extract valuable i