Tapping Mode AFM
In original meaning the mode in which a probe tip is oscillated at a resonant frequency and at amplitude setpoint and scanned across the surface of a sample in contact with the sample, so that the amplitude of oscillation of the probe is changed in relation to the topography of the surface of the sample. The setpoint amplitude of oscillation of the probe is greater than 10 nm to assure that the energy in the lever arm is much higher than that lost in each cycle by striking the sample surface, thereby to avoid sticking of the probe tip to the sample surface.
US Pat. 5412980: Tapping atomic force microscope
At present time by tapping-mode AFM one means a high-amplitude dynamic mode where an amplitude modulation feedback is used to image the sample topography. The cantilever-tip ensemble is oscillatedat a frequency close to its resonance. The sample is imaged while the feedback adjusts the tip-sample separationto keep the oscillation amplitude at a fixed value. There are two regimes of tapping mode — with attractive and repulsive tip-sample interactions.
Phys. Rev. B 60, 4961 (1999).
Transverse Dynamic Force Microscopy Transverse dynamic force microscopy (TDFM) is a Dynamic Probe Microscopy in which the detected force is perpendicular to the probe, hence "transverse". The first use of this technique has been the Shear Force Microscopy. In TDFM, the cantilever is oriented perpendicularly to the sample and oscillates parallel to its surface. The interaction between the tip and the sample can be measured at different separations by observing the change in amplitude and the relative phase of the cantilever oscillation. The shear force is often used in TDFM to obtain topographic images of the surface. The oscillation amplitude of the probe decreases monotonically when approaching the surface; by using the amplitude signal in a feedback loop it is therefore possible to scan the surface at constant height. If the system is monitoring amplitude and phase at the same time, it is also possible to record phase information while keeping the amplitude constant.
Langmuir 17, 349 (2001). Appl. Phys. Lett. 78, 300 (2001).
Transmission Electron Microscopy
Tip-enhanced Raman Spectroscopy
Thermal Scanning Microscope, Scanning Thermal Microscope, SThM
ThSM is based upon a noncontacting near-field thermal probe. Profiling is achieved by scanning the heated sensor above but close to the surface of a solid. The conduction of heat between tip and sample via the air provides a means for maintaining the sample spacing constant during the lateral scan.
Appl. Phys. Lett. 49, 1587 1986.
Total indicated runout
total internal reflection
Phys. Rev. B 39, 767 (1989).
Tapping Mode AFM
Total measurement uncertainty
metric for comparing a set of measurements to a set of reference measurements (SEMATECH)
A precursor of SPM, invented by Russell Young and colleagues between 1965 and 1971 at the National Bureau of Standards (NBS).
Loading force, force of cantilever pressure on the sample surface.
Rev. Sci. Inctr. 69, 2085 (1998).
tunneling current and surface-potential simultaneous measuring system
TSM is the system for tunneling current and surface potential simultaneous measuring. The distance (d) between a sample and a probe tip is changed sinusoidally with high precision. The tunneling current flows periodically in accordance with the vibration of the tip when d becomes as small as a few nm. The surface potential is measured using the principle of the Kelvin method in which the displacement current due to the presence of surface potential and the change in capacitance difference between the tip and the sample is detected. Simultaneous measurement of the tunneling current and the displacement current has been attained by utilizing their phase difference in tip vibration.
Jpn. J. Appl. Phys. 37, 4557 (1998); Phys. Rev. B 62, 1971 (2000).
Tunneling stabilized MFM
Appl. Phys. Lett. 49, 1587 (1986).
High Q piezoelectric tuning forks with attached to their prongs fibers and tips are used as a force sensors in ShFM and Tuning-Fork-Based AFM, alsow qPlus-sensor (QPS).
AFM with tuning-fork-based height feedback. The attached to a one prong probe tip oscillates normally to a sample surface, as in light-lever based noncontact AFM. The advantages of tuning-fork-based are follows: the tuning fork is a chip, small hight detector,no optical alignement is needed, simple and compact instrument can be designed.
Appl. Phys. Lett. 75, 1640 (1999).