Oberflächenmikroverfahren

Oberflächenmikroskopie, or surface microscopy, is a field of microscopy dedicated to imaging and characterizing surfaces at micro- to nanometer-scale resolution. It covers a range of techniques designed to reveal topography, roughness, structure, and sometimes mechanical or chemical properties of material surfaces. The aim is to understand surface phenomena that influence adhesion, wear, catalysis, and electronic behavior.

Principal techniques include scanning probe microscopy (SPM), such as atomic force microscopy (AFM) and scanning tunneling microscopy (STM); electron microscopy with a surface focus, particularly scanning electron microscopy (SEM); and optical or near-field methods like confocal laser scanning microscopy and near-field scanning optical microscopy (NSOM).

AFM uses a sharp tip mounted on a flexible cantilever that deflects in response to surface forces, providing topographic maps with sub-nanometer vertical resolution. It can operate in air or liquid and in several modes (contact, tapping, non-contact).

SEM scans a focused electron beam across the surface, producing secondary or backscattered electrons to form images with high lateral resolution; high vacuum and conductive samples are typical. STM images electron density by measuring tunneling current between a tip and surface, achieving atomic-scale resolution but requiring conductive samples and often ultrahigh vacuum or specialized environments.

NSOM solves the diffraction limit by using a sub-wavelength optical probe to map optical and near-field properties; optical profilometry, including white-light interferometry, measures surface roughness and height non-destructively over larger areas.

Applications span materials science, semiconductors, nanotechnology, biology (cell-surface interfaces), tribology, and corrosion studies, as well as quality control in manufacturing. The field developed through the 20th century with major advances in electron-based imaging and the invention of scanning probe techniques in the 1980s, shaping modern surface science.

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