Regensburg 2007 – scientific programme

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O: Fachverband Oberflächenphysik

O 59: Oxides and Insulators: Clean Surfaces

O 59.9: Talk

Thursday, March 29, 2007, 17:45–18:00, H41

Photon Mapping of MgO thin Films with an STM — •Hadj-Mohamed Benia, Niklas Nilius, and Hans-Joachim Freund — Fritz-Haber-Institut der MPG, Berlin

The light emission from an STM junction consisting of an MgO thin film on Mo(001) and an Au tip is analysed with respect to its spatial distribution for various excitation conditions. The spectral characteristic of the light is compatible with an emission mechanism mediated by tip-induced plasmons that are excited by inelastic tunnel processes involving field emission resonances in the tip-sample gap. For MgO islands of distinct topographic height, the local emission yield can be tuned by changing the sample bias. This interrelation reflects the dependence of field emission resonances on the MgO work function, which in turn is a function of the number of MgO layers covering the Mo support.