Atomic force microscopy tip

J. R. Krogmeier and R. C. Dunn, Focused ion beam modification of atomic force microscopy tips for near-field scanning optical microscopy, Appl. Phys. Lett., 79 (2001) 4494-4496. 

C.L. Cheung, J.H. Hafner, C.M. Lieber, Carbon Nanotube Atomic Force Microscopy Tips Direct Growth by Chemical Vapor Deposition and Application to High-Resolution Imaging , Proc. Natl. Acad. Sci. USA, 97, 3809 (2000)... 

Dip-pen nanolithography is a high resolution patterning technique that enables the creation of patterns from the sub lOOnm to many micrometers length scale.76 This technique uses an ink-coated AFM (atomic force microscopy) tip as a nanopen. The ink molecules are transported from the tip to a substrate, normally by capillary forces when the tip is in contact with the surface of the substrate.77 The driving force for such transport is chemisorption of the ink to the underlying substrate due to a chemical78 or electrochemical force.79... 

Figure 3.45 Measuring the mechanical properties of a single nanotube by means of two atomic force microscopy tips scheme (a) and microscope image (b). The torn and markedly elongated nanotube is clearly to be seen ( ACS 2000).

X. Luo, V. A. Pedrosa, and J. Wang, Enzymatic nanolithography of polyaniline nanopatterns hy using peroxidase-modified atomic force microscopy tips, Chem. Eur. J., 15, 5191-5194 (2009). 

Sun, Y., Akhremitchev, B., and Walker, G. C., Using the adhesive interaction between atomic force microscopy tips and polymer surfaces to measure the elastic modulus of compliant samples, Langmuir, 20, 5837-5845 (2004). 

Kocum C, Ulgen SD, Cubukcu E, Piskin E (2006) Atomic force microscopy tips (cantilevers) as molecular nucleic acid sensors. Ultramicroscopy 106 326-333... 

Ebner A, Wildling L, Kamruzzahan ASM, Rankl C, Wmss J, Hahn CD, et al. A new, simple method for linking of antibodies to atomic force microscopy tips. Bioconjugate Chem. 2007 18(4) 1176-84. 

B., Yu, G., and Liu, Y.Q. (2012) Multilayer graphene-coated atomic force microscopy tips for molecular junctions. Adv. Mater, 24, 3482- 3485. 

Cross-linked elastomers have been studied with regard to their moduli (particularly plateau values), effects of peroxide cross linking, adhesive interactions with atomic force microscopy tips, and the effects of phenyl-group modifications. Investigations on networks containing fillers include the effects of silica or polysilicate nanoparticles, zero... 

The WITec alphaSOO R confocal Raman microscope can be upgraded to perform atomic force microscopy, tip-enhanced Raman spectrometry, and near-field scanning optical microscopy, and is arguably the most versatile instrument for Raman microspectroscopy available today, although the competition is rapidly closing the gap. 

Zhu, L. et al (2007) Nano-Raman spectroscopy with metallized atomic force microscopy tips on strained silicon structures. /. AppL Phys., 101, 104305. doi 10.1063/1.2732435... 

The ability to control the position of a fine tip in order to scan surfaces with subatomic resolution has brought scanning probe microscopies to the forefront in surface imaging techniques. We discuss the two primary techniques, scanning tunneling microscopy (STM) and atomic force microscopy (AFM) the interested reader is referred to comprehensive reviews [9, 17, 18]. 

The most popular of the scanning probe tecimiques are STM and atomic force microscopy (AFM). STM and AFM provide images of the outemiost layer of a surface with atomic resolution. STM measures the spatial distribution of the surface electronic density by monitoring the tiumelling of electrons either from the sample to the tip or from the tip to the sample. This provides a map of the density of filled or empty electronic states, respectively. The variations in surface electron density are generally correlated with the atomic positions. 

Perez R, Payne M C, Stich i and Terakura K 1997 Roie of covaient tip-surface interactions in noncontact atomic force microscopy on reactive surfaces Phys. Rev. Lett. 78 678... 

Miyatani T, Florii M, Rosa A, Fu]ihira M and Marti O 1997 Mapping of electric double-layer force between tip and sample surfaces in water with pulsed-force-mode atomic force microscopy Appl. Phys. Lett. 71 2632... 

Advances have been made in directly measuring the forces between two surfaces using freshly cleaved mica surfaces mounted on supports (15), and silica spheres in place of the sharp tip of an atomic force microscopy probe (16). These measurements can be directly related to theoretical models of surface forces. 

Yet another modification is atomic force microscopy (ATM), in which a fine tip attached to a tiny flexible beam is scanned across the surface. The atom at the end of the tip experiences a force that pulls it toward or pushes it away from the atoms on the surface. The deflection of the beam, which shows the shape of the surface, can he monitored by using light from a laser. 

Atomic force microscopy (AFM) has been used to characterize dendrimers that have been adsorbed onto a surface such as silica. AFM involves moving a finely tipped stylus across a surface and monitoring the tip movements as it traces the surface topography. In studying adsorbed dendrimers, samples can be scanned repeatedly and in a variety of directions. When this is done, it is found that all the images are the same. True dendrimers form objects of only one size. 

Ebenstein, Y., Nahum, E., and Banin, U., Tapping mode atomic force microscopy for nanoparticle sizing Tip-sample interaction effects, Nano Lett., 2, 945, 2002. 

Atomic force microscopy (AFM) or, as it is also called, scanning force microscopy (SFM) is based on the minute but detectable forces - of the order of nano Newtons -between a sharp tip and atoms on the surface. The tip is mounted on a flexible arm, called a cantilever, and is positioned at a subnanometre distance from the surface. If the sample is scanned under the tip in the x-y plane, it feels the attractive or repulsive force from the surface atoms and hence it is deflected in the z-direction. The deflection can be measured with a laser and photo detectors as indicated schematically in Fig. 4.29. Atomic force microscopy can be applied in two ways. 

Figure 4.29. Experimental set-up for atomic force microscopy. The sample is mounted on a piezo electric scanner and can be positioned with a precision better than 0.01 nm in thex, y, and z directions. The tip is mounted on a flexible arm, the cantilever. When the tip is attracted or repelled by the sample, the deflection of the cantilever/tip assembly is...

The combination of atomic force microscopy (AFM) and Raman spectroscopy is another approach to attain high spatial resolution. AFM also employs a sharp tip close to a sample surface. When the tip is made of metal and light is irradiated onto the tip and surface, Raman scattering is largely enhanced. In this way, a spatial resolution of 15 nm is achieved [2]. 

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