Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 60: Poster Session III (Methods: Atomic and electronic structure; Methods: electronic structure theory; Methods: Molecular simulations and statistical mechanics; Methods: Sanning probe techniques; Methods: other (experimental); Methods: other (theory) )

O 60.19: Poster

Mittwoch, 24. März 2010, 17:45–20:30, Poster B2

Investigating structured surfaces with a near-field scanning thermal microscope using a new scanning method — •Lars Hoelzel, Uli F. Wischnath, and Achim Kittel — University of Oldenburg - Energy an Semiconductor Research Laboratory - C. v. Ossietzkystr. - D 26111

The near-field scanning thermal microscope (NSThM) [1] is able to measure the thermal flux between a modified tip of a STM and a heated or cooled sample surface under ultra-high vacuum conditions. Hence, the main contribution is mediated by evanescent electro-magnetic fields. Up to now the heat flux was investigated in constant current mode of the STM on which the NSThM is based [2]. While the tunnelling current decays on a short length scale the heat flux decays on a roughly ten times larger length scale. The new scan mode employs a control loop which keeps the heat current constant. Therefore, it is possible to investigate the influence of the surface morphology on the heat flux at larger distances. The results gained by the constant thermovoltage mode suggest that the evanescent field reaches farther out in trenches compared to a convexly curved surface or even a flat surface.

[1] Uli F. Wischnath et al., Rev. Sci. Instrum. 79, 073708 (2008)

[2] Achim Kittel et al., Appl. Phys. Lett. 93, 193109 (2008)