Scanning Kelvin Microscopy

Principles and Characteristics The vibrating capacitor or Kelvin method [362, 363] is a well-established experimental technique for measuring the contact potential difference (CPD) or work function for a variety of materials, including polymers [364] and carbon-black [365]. Here, the sensitivity of the CPD to the appearance of electronic surface states and surface charges is used. Scanning Kelvin microscopy (SKM) allows for mapping of the two-dimensional CPD distribution on sample areas of 1 cm with /u.m resolution without extensive experimental requirements [366]. 

The experimental setup for SKM is shown in Fig. 5.8. The sensing element is a tungsten tip about 50 /u.m in diameter positioned at a distance of 10 /u.m above the sample surface. The sample is mounted on a x-y translation stage, above which the oscillating tungsten tip is positioned, which is leveled before the scan. An applied external voltage Ue is fixed, and the induced Kelvin current is measured at each position with a lock-in amplifier. 

SKM is a non-destructive investigation method for revealing the distribution of the conductive net- 

Although not a scanning probe microscopy at the atomic level, scanning Kelvin microscopy shows some (macroscopic) similarities to SPM methods. At variance to STM, SKM measurements are performed with a tip operating in the far-held ptm Vi. nm scale). 

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T. Prasse, A. Ivankov, J. Sandler, K. Schulte, W. Bauhofer (2001) Imaging of conductive filler networks in heterogeneous materials by scanning Kelvin microscopy, J, Appl. Polym. Sci. 82,3381. 

Hallam T, Lee M, Zhao N, Nandhakumar I, Kemerink M, Heeney M, McCulloch I, Sirringhaus H (2009) Local charge trapping in conjugated polymers resolved by scanning Kelvin probe microscopy. Phys Rev Lett 103 256803... 

Fig. 12.7. Assessment of channel length of SAP-defined source-drain electrodes (A) top-view environmental scanning electron microscopy (ESEM) image of channel region (B) Scanning Kelvin probe microscopy of...

Many-pass techniques Electric Force Microscopy (EFM) Scanning Capacitance Microscopy (SCaM) Kelvin Probe Microscopy (SKM) DC Magnetic Force Microscopy (DC MFM) AC Magnetic Force Microscopy (AC MFM) Dissipation Force Microscopy-Scanning Surface Potential Microscopy (SSPM) Scanning Maxwell Stress Microscpy (SMMM) Magnetic Force Microscopy (MFM) Van der Waals Force Microscopy (VDWFM)... 

A further spatially resolved method, also based on work function contrast, is scanning Kelvin probe microscopy (SKPM). As an extended version of atomic force microscopy (AFM), additional information on the local surface potential is revealed by a second feedback circuit. The method delivers information depending on the value (p (p(x) + A x). Here, A(zS(x) is the difference in work function between the sample and the AFM tip and cp(x) is the local electric potential [12]. (p x) itself gives information on additional surface charges due to... 

FIGURE 2.3.12 (a) Schematic diagram of experimental setup for scanning Kelvin probe microscopy (SKPM). (b) Profiles of an L = 5.5 J,m P3HT transistor with Cr electrodes taken at three different temperatures V = 0 V, = -8 V). The inset shows a profile obtained after switching the source and drain contacts on the same TFT with both Cr and Cr-Au contacts Vg = 0 V, = -8 V). (From Burgi, L. et ah, J. Appl. Phys., 94, 6129-6137, 2003. Reprinted with permission. Copyright 2003, American Institute of Physics.)... 

Characterizing these many aspects of microstructure is necessary to establish relationships between primary chemical structure, processing, and performance. Currently, the most commonly used methods are scanning probe microscopy techniques such as atomic force microscopy (AFM) or kelvin probe force microscopy... 

Scanning Kelvin Probe Force Microscopy (SKPFM)... 

SKPFM Scanning Kelvin probe force microscopy... 

Measurements of topography from optical microscopy, scanning electron microscopy (SEM), scanning tunnelling microscopy (STM), atomic force microscopy (AFM), Laser profilometry, Kelvin- and electrochemical probes. 

K. Maturova, M. Kemerink, M.M. Wienk, D.S.H. Charrier, and R.A.J. Janssen, Scanning Kelvin probe microscopy on bulk heterojunction polymer blends. Adv. Funct. Mater., 19, 1... 

A number of methods have applications in studies of corrosion, such as Kelvin probe atomic force and chemical force and scanning tunneling methods. Of these techniques, atomic force microscopy and scanning tunneling microscopy are the most commonly used for roughness measurements. NSOM and SNOM are scanning probe methods used to obtain optical imaging or some form of contrast. 

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