Constant height imaging

Fig. 8. Surface structure of a single crystal of perfluorododecyleicosane F(CF2 )12(CH2)20H measured by contact mode SFM on the (a) micrometer and (b) nanometer scale. The constant height image in (a) shows variation of the normal force, while the constant force image in (b) displays variation in height caused by densely packed CF3 end groups protruding at the surface...

STM imaging modes are either constant current imaging (CCI) or else constant height imaging (CHI). The CCI mode is the most commonly used method of imaging. The STM tip is scanned laterally (x, y) across a sample surface by variations in the respective and Uy... 

FIGURE 1.2 (a) Constant-height image of an interdigitated array electrode obtained by... 

FIGURE 1.9 (a) Constant-current and (b) constant-height images of a human breast epi-... 

Fig. 39 Bias-dependent STM constant-height images of 42 (15.5 x 15.5 nm ) at the 1-phenyloctane-graphite interface. The sample bias is indicated. D refers to the donor and A to the acceptor moiety, respectively. (Reproduced with permission from Ref. [117])...

In case of passive tip, when feedback effect is not available other distance measuring method has to be selected. Double barrel tip, one barrel for imaging, the other one for distance measuring, has been successfully applied [51,52]. In case of pH imaging double function antimony tip [62] could be used for both distance measurement (amperometric mode) and potentiometric mode (pH imaging). The constant height imaging mode is appropriate in case of thin film samples. It requires simpler apparatus. 

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