The Dimension 3100 (Veeco Digital Instruments by Bruker) is the state-of-the-art multi-mode atomic force microscope (AFM), equipped with a NanoScope IIIa controller and Quadrex signal processor for 16-bit resolution on all 3 axes. The instrument operates under atmospheric pressure at room temperature and works in air, so that a full range of materials (metals, insulators, ceramics, polymers, and biological specimens) can be investigated with minimal sample preparation. It can accept samples (diameter up to 20 cm in diameter, height up to 1.5 cm, surface roughness up to 5.5 mm). The AFM is equipped with an in-line optical zoom microscope with color CCD camera, with a maximum magnification of 800x for precise placement of the probe onto the sample.
The AFM can operate in numerous imaging modes, the primary operation being atomic force microscopy (AFM) in contact mode, tapping mode, and phase imaging mode. Other data collection techniques include conductive-AFM to characterize conductivity variations; magnetic force microscopy (MFM), which uses a ferromagnetic-coated tip to probe magnetic fields; and force-distance measurements, which are performed to study attractive and repulsive forces on a tip as it approaches and retracts from the sample surface.
The AFM system is equipped with comprehensive image analysis software. Full 2D and 3D mapping and displays can be generated, with a variety of slope and flatness corrections. Ra and rms roughness calculations can be done on selected areas, as well as a multitude of additional statistical calculations. Image files can be exported in tif, ascii, and jpg formats.
The Dimension 3100 AFM has been upgraded by a "TriboScope," an attachment for nanomechanical testing, made by Hysitron. The TriboScope is a quantitative, depth-sensing nanoindentation and nanoscratch system that interfaces with the AFM. This attachment enables quantitative characterization of mechanical properties (hardness, scratch resistance, wear resistance) on the nanometer length scale and in situ AFM imaging of the surface topography before and after mechanical testing. The capability of in situ imaging allows the user to choose the exact area, with sub-nm precision, for each nanoindentation/nanoscratch investigation, and to fully characterize the local specimen surface. Thus, the user can minimize the effects of random surface roughness, can investigate specific features or phases, and can place indents within nanometers of interfaces. This is particularly useful for profiling cross-sectional specimens. Post-mechanical testing imaging also provides information on fracture toughness, adhesion, and interface strength, among other properties.
The Triboscope comes with data analysis software that provides hardness, reduced modulus, and specimen stiffness, in addition to the raw load-depth data. The tool operates in load control with a maximum load is 9500 mN. The loading and unloading rates are fully operator-controlled, allowing additional investigations, such as creep rate, anelasticity, and loading-rate effects.