Regensburg 2010 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 9: SC: Poster Session
TT 9.54: Poster
Monday, March 22, 2010, 14:00–18:00, Poster A
Spatially Resolved Photoresponse of NbN Nanowires — •Philipp Jung1, Alexander Lukashenko1, Alexander P. Zhuravel2, Stefan Wuensch1, Matthias Hofherr1, Konstantin Ilin1, Michael Siegel1, and Alexey V. Ustinov1 — 1Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany — 2B. Verkin Institute for Low Temperature Physics & Engineering, Kharkov Ukraine
We are investigating optical response of superconducting nanowires patterned from thin NbN films deposited on sapphire and Si substrates. These structures are often used for radiation detectors like single-photon detectors and hot-electron bolometer mixers. In our experiments, we precisely position a focused laser beam on the detector to correlate the response to a local excitation. Scanning the laser spot over the sample surface allows us to obtain response maps of the investigated wires.
We have found spatially localized weak areas in case of NbN films on sapphire substrates, which can be attributed to grain boundaries with suppressed superconducting properties. In opposite, the strongest response of NbN bridges on Si substrates was obtained at the edges of bridges. We are going to present and analyze the dependence of response of NbN thin film bridges on light intensity and operation temperature.