Regensburg 2016 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 12: Postersession DS
DS 12.47: Poster
Montag, 7. März 2016, 17:00–19:00, Poster A
Spectroscopic near-field investigation of trigonally symmetric contrasts on solvothermally grown Sb2 Te3 platelets in the mid-infrared. — •Lars Mester1, Martin Lewin1, Tobias Saltzmann2, Ulrich Simon2, and Thomas Taubner1 — 1I. Physikalisches Institut A, RWTH Aachen — 2Institut für Anorganische Chemie, RWTH Aachen
Chemical syntheses could provide a cheap alternate approach to conventional nanofabrication as e.g. gas-phase deposition techniques [1]. Solvothermally synthesised Sb2 Te3 platelets of 2−3 µ m size grown under various synthesis conditions are spectroscopically investigated via scanning near-field microscopy (SNOM) at various mid-infrared wavelengths. In SNOM measurements, laser light is focused on an AFM tip which is scanned in tapping mode over the sample. Backscattered light from the tip is influenced by near-fields of the sample and enables microscopy and spectroscopy beyond the diffraction limit with lateral resolution in the order of the AFM tip radius (≈ 25 nm) [2].
The investigated single-crystalline Sb2 Te3 platelets show unexpected domains of several 100 nm lateral extent with different optical response. By modeling the response with the Drude model and Finite Dipole Model, Hauer et al attributed the domains to regions of two different charge carrier concentrations [3]. Further analysis of the Drude characteristics is made with SNOM spectroscopy between 900−1900 cm−1.
[1] Saltzmann et al, Angew. Chem. Int. Ed. 54, pp. 6632-6636 (2015)
[2] Taubner et al, J. of Microsc., 210, Pt 3, pp. 311-314 (2003)
[3] Hauer et al, Nano Lett. 15, pp. 2787-2793 (2015)