ISSN:
1077-3118
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Epitaxial Ag(111) films have been grown on mica. They exhibit flat terraces of a few 100 nm diameter, suitable for nanoscale modification with the scanning tunneling microscope (STM). Under ambient conditions, surface modifications of a few nanometers diameter were produced by raising the bias from below 1 V to a bias between 3 and 7 V for less than 50 ns. The steady-state current could be limited to 2 pA. This means that the modification is initiated while only a few electrons pass the tunneling junction, indicating that it is not a current effect. At positive sample bias, usually holes are formed, while at negative bias hillocks occur. In the case of hole formation, the current does not change significantly on a time scale of 10 μs. When hillocks are formed, the current may rise after the application of the voltage pulse. It was limited to 4 nA by the external circuitry and remains saturated until the tip is withdrawn on a time scale of milliseconds, i.e., the characteristic for the feedback loop control. Also in this case the modification is not caused by a current effect, since the limiting current would still allow nondestructive STM imaging. It is concluded that the modifications are caused by field evaporation of sample and tip material, respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.104520
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