ScanningProbeMikroskope

Scanning Probe Microscopy (SPM) is a family of high-resolution imaging techniques that map surface structure and properties by bringing a sharp probe close to a sample and recording the interaction between the tip and surface as the tip scans. The techniques can measure topography, electrical, magnetic, thermal, and mechanical properties at the nanoscale.

The field originated with the invention of scanning tunneling microscopy (STM) in 1981 by Binnig, Rohrer, and coworkers, which images conductive surfaces by measuring tunneling current between a bias-applied tip and the sample. Atomic Force Microscopy (AFM) followed in 1986, using a compliant cantilever to sense interatomic forces, enabling imaging of non-conductive samples.

Variants include scanning near-field optical microscopy (SNOM or NSOM) for optical contrast, Kelvin probe force microscopy (KPFM) for surface potential, magnetic force microscopy (MFM) for magnetic domains, and others that combine AFM with simultaneous measurements of electrical, thermal, or spectroscopic signals.

In practice, a sharp tip mounted on a cantilever is scanned over the surface by piezoelectric actuators while a detector measures deflection, resonance, or tunneling current. A feedback loop maintains a prescribed interaction, producing a topographic image or mapped property. Experiments may be conducted in air, liquid, or ultra-high vacuum.

Applications include characterizing material surfaces, nanoscale metallurgy, semiconductor devices, polymers, biomaterials, and energy materials. Limitations include tip convolution effects, potential sample damage, slow imaging speed, and the need for careful calibration. Ongoing developments aim at faster imaging, quantitative property mapping, and integrated multi-modal measurements.