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Constant‐Distance Mode Scanning Electrochemical Microscopy (SECM)—Part I: Adaptation of a Non‐Optical Shear‐Force‐Based Positioning Mode for SECM Tips
Author(s) -
Ballesteros Katemann Bernardo,
Schulte Albert,
Schuhmann Wolfgang
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200204267
Subject(s) - scanning electrochemical microscopy , optics , signal (programming language) , amplifier , shear force , materials science , non contact atomic force microscopy , piezoelectricity , vibration , amplitude , acoustics , optoelectronics , microscopy , physics , kelvin probe force microscope , electrode , cmos , quantum mechanics , composite material , computer science , electrochemistry , programming language
A non‐optical shear‐force‐based detection scheme for accurately controlling the tip‐to‐sample distance in scanning electrochemical microscopy (SECM) is presented. With this approach, the detection of the shear force is accomplished by mechanically attaching a set of two piezoelectric plates to the scanning probe. One of the plates is used to excite the SECM tip causing it to resonate, and the other acts as a piezoelectric detector of the amplitude of the tip oscillation. Increasing shear forces in close proximity to the sample surface lead to a damping of the vibration amplitude and a phase shift, effects that are registered by connecting the detecting piezoelectric plate to a dual‐phase analogue lock‐in amplifier. The shear force and hence distance‐dependent signal of the lock‐in amplifier is used to establish an efficient, computer‐controlled closed feedback loop enabling SECM imaging in a constant‐distance mode of operation. The details of the SECM setup with an integrated piezoelectric shear‐force distance control are described, and approach curves are shown. The performance of the constant‐distance mode SECM with a non‐optical detection of shear forces is illustrated by imaging simultaneously the topography and conductivity of an array of Pt‐band microelectrodes.