| EFM |
|
|
|
Generally Electric Force Microscopy (EFM) can be used in several modes,
depending on the type of the sample under investigation and kind of the
required information.
The most useful of them is Non-Contact EFM
mode based on the two-pass technique. During the second pass the
cantilever is piezodrived at resonant frequency and cantilever is
grounded or biased by dc voltage V. Capacitive tip-sample electric
force (or rather its derivative) leads to resonance frequency shift.
Accordingly amplitude of cantilever oscillation decreases and phase of
oscillation changes [1].
Both amplitude and (or) phase of oscillation deviations can be measured
and electric potential distribution over the sample surface can be
imaged.
This mode of operation has some advantages comparatively to Scanning Kelvin Microscopy (SKM).
Registered amplitude or phase deviations images are determined by
capacitive tip-sample electric force derivative, e.g. second derivative
of tip-sample capacity. As a result Non-Contact EFM leads to higher
resolution because the ratio of the parasitic capacitance of the tip
side and of the flat part of the cantilever to the useful capacitance
of the tip apex should is minimized [2,3].
References
Copyright © 1998-2007, NT-MDT. All rights reserved.
|
| < Prec. | Pros. > |
|---|
