Hofmann, Thomas and Welker, Joachim and Giessibl, Franz J. (2010) Preparation of light-atom tips for scanning probe microscopy by explosive delamination. Journal of Vacuum Science & Technology B 28 (3), C4E28.
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To obtain maximal resolution in scanning tunneling microscopy (STM) and atomic force microscopy, the size of the protruding tip orbital has to be minimized. Beryllium as tip material is a promising candidate for enhanced resolution because a beryllium atom has just four electrons, leading to a small covalent radius of only 96 pm. Besides that, beryllium is conductive and has a high elastic modulus, which is a necessity for a stable tip apex. However, beryllium tips that are prepared ex situ are covered with a robust oxide layer, which cannot be removed by just heating the tip. Here, the authors present a successful preparation method that combines the heating of the tip by field emission and a mild collision with a clean metal plate. That method yields a clean, oxide-free tip surface as proven by a work function of Φexpt = 5.5 eV as deduced from a current-distance curve. Additionally, a STM image of the Si-(111)-(7×7) is presented to prove the single-atom termination of the beryllium tip.
|Institutions:||Physics > Institute of Experimental and Applied Physics > Chair Professor Giessibl > Group Franz J. Giessibl|
|Projects:||GRK 1570, Elektronische Eigenschaften von Nanostrukturen auf Kohlenstoff-Basis|
|Subjects:||500 Science > 530 Physics|
|Created at the University of Regensburg:||Unknown|
|Deposited On:||10 Jul 2012 13:50|
|Last Modified:||27 Feb 2014 09:01|