Atomic metallic ion emission, field surface melting and scanning tunneling microscopy tips

Abstract

This work presents the physical realisation of metallic ion beams from atomic emitters with currents of approximately 105 ions per second. It also puts forward the idea of field surface melting at approximately one third of the bulk melting temperature. Under cooling this melted surface, experiments show pyramidal structures of nanometer dimensions ending in one atom also separated by nanometers, then shaping surface grain boundaries. Furthermore, this reveals why it is possible to have atomic resolution in STM experiments. The formation of double, triple, etc. atomic teton tips is also possible. All this is shown by field ion and field emission microscopies and atomic metallic ion emission experiments presented here for tungsten tips

STEM observation of tungsten tips sharpened by field-assisted oxygen etching

“…One type of ultra-sharp tip is widely known as a single-atom termination tip, which has three-sided pyramid terminated apex in the nanoscale [5][6][7][8][9][10][11][12]. Single-atom tips on which noble metals are deposited [9][10][11][12] are especially thermodynamically stable; even if the topmost atomic structures are destroyed, they can return to the single-atom termination tip only by heat treatments.…”

Dynamic processes on a surface of iridium field emitters produced by the actions of high temperature and electric field

“…The value F 1.0 v/A decreases Q from 6.93 to 1.67 eV, but in the case of low temperature field evaporation evaporating field F = 5.3 V/A decreases Q down to zero practically. 4. CONCLUSIONS 1 .…”

Visualizing Chemistry: The Progess and Promise of Advanced Chemical Imaging

“…Further treatments are sometimes used to sharpen them, such as annealing under high fields 133,134 in techniques handed down from the original atomic resolution microscopies-field emission microscopy and field ion microscopy. 135,136 Another method employed is to lift an atom or molecule onto the probe tip so as to define the tip precisely.…”