2010/01/08 by Thomas Hofmann, Joachim Welker, Franz J. Giessibl +1
Chemistry · Engineering · Physics and Astronomy · #Atom (system on chip) #Atomic physics #Beryllium #Beryllium oxide #Chemistry #Composite material #Electron #Explosive material #Field electron emission #Force Microscopy Techniques and Applications #Integrated Circuits and Semiconductor Failure Analysis #Layer (electronics) #Materials science #Metallurgy #Molecular physics #Nanotechnology #Oxide #Physics #RADIUS #Surface and Thin Film Phenomena #Work function #cond-mat.mes-hall
paper · pdf · doi:10.1116/1.3294706
to be published in JVST B May/June 2010
arxiv created 2010/01/08 · openalex publication_date 2010/05/01 · arxiv updated 2015/05/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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.