Principle

AFM is one of the most widely used surface observation and research tools in SPM family. The principle of AFM is based on the interaction (atomic force) between microprobe and sample. When a sharp microprobe approaches a sample to a very short distance S, such as several nanometers or smaller, an atomic force F will occur between the atoms of microprobe tip and those of sample surface. In accordance with the F-S relationship curve, attractive atomic force is dominant when the distance is comparatively larger, while repulsive atomic force becomes predominate as the distance getting much smaller. On the basis of these relationships, AFM is able to obtain 3D micro/nano-morphology of sample surface by detecting atomic forces using beam deflection method when a cantilever-combined microprobe scans over the sample.

Instrument Overview

AFM uses a micro cantilever that is extremely sensitive to weak forces as a force sensor-a micro probe. One end of the micro cantilever is fixed, and the other end is provided with a pyramid-shaped micro needle tip perpendicular to the plane of the micro cantilever. When the distance between the needle tip and the sample approaches to a certain degree, there will be an interaction of atomic forces between them, where the tangential force (frictional force) Ft twists the microcantilever, and the normal (longitudinal) forceFn will push the microcantilever to deflect . Our main concern is the longitudinal force Fn, which has a certain correspondence with the needle tip-sample spacing, that is, with the fluctuation of the sample surface. The deflection of the microcantilever is very small and cannot be directly detected. Using optical methods to amplify the deflection, the size of the microcantilever deflection (ie, atomic force) can be inferred, and the microscopic morphology of the sample surface is finally obtained.

Feature

Specially-designed horizontal AFM probe unit

The SEK-8502 AFM owns a specially-designed horizontal AFM probe unit to eliminate the interference between atomic force and gravity.

It is also able to reduce the center of gravity and avoid the vertical creeps of coarse and fine adjustment mechanisms. Moreover, the AFM probe unit enables visualization of the optical path. In these ways, the novel AFM and its probe unit is of more stability and superior performances.

Stabilized tri-axial piezoelectric scanner

It utilizes a stabilized tri-axial piezoelectric scanner which is able to eliminate the coupling of X, Y and Z piezoelectric elements between each other, as to avoid the image distortion. The scanner ensures better scanning linearity and independence, higher intensity and rigidity, as well as stronger driving force. Therefore, the scanner as well as the AFM instrument is more suitable for scanning small and/or large, light and/or heavy samples.

Optimized scanning and feedback controlling system

With optimized scanning and feedback controlling system and multi-channel high-precision A/D&D/A interfaces, the AFM owns higher scanning and imaging resolution, better repeatability and enhanced image quality.

Perfect software interfaces and functions

Powerful, friendly interface, can be applied to operating systems such as Windows XP / Win7 / Win8 / Win10. General operators can easilyand skillfully master, and all operations from image scanning to image processing and data information calculation can be completed with just a mouse click. The local scanning area can be arbitrarily selected with the mouse to achieve image translation, positioning and zooming; the number of scans can be set and the scanning stop can be automatically controlled; it has the functions of surface scanning and line scanning in the X and Y directions; nano-scale three-dimensional sample surface can be obtained Morphology structure and section line; high-quality color / black and white flat image display and three-dimensional stereoscopic image display; with two-dimensional and three-dimensional nanoscale labeling function and particle size measurement function; with statistics and calculation of nano-level surface micro-roughness Function; can accurately measure the height and depth of micro-nano steps on the surface of thesample; perfect image processing functions, including cropping, pasting, rotation, contrast adjustment,   brightness adjustment, color adjustment, background color adjustment, image smoothing, filtering, etc.

Simple and convenient instrument operation

The operation of this AFM is quite simple and convenient so that any ordinary user and learner can carry out the operation, while no professional and skilled staff is demanded. Each process of probe tip installation, sample installation, coarse and fine approaching, image scanning, image acquisition and other operations can be completed within 1 minute for each. Therefore, It is much more suitable for scientific research, teaching experiments and product testing.

High stability and better anti-disturbance/interference performances

The AFM can work perfectly under both good and common experimental conditions. It is capable of scanning samples and obtaining satisfactory images in general laboratories and rooms, on ordinary desks or tables, and under environments with slight vibration, disturbance and interference, etc. In other words, it is of better stability, better anti-disturbance capability, stronger anti-(optical, electric, electronic, and magnetic, etc.) interference performances, and faster scanning speed (up to 1 image/1~6 seconds).

High applicability in wide application fields

The AFM can be widely applied in scientific research, undergraduate and graduate teaching experiments and nano-products testing.

It is suitable for scanning and imaging various materials such as metals/nonmetals, conductors/semiconductors/non-conductors, and magnets/non-magnets, etc, while no special requirement of sample preparation is demanded.

Experiments and data

Some sample images scanned using the AFM

Part list