scanningtunnelingmikroskopi

Scanning tunneling microscopy (STM) is a powerful technique used in surface science to image and study the atomic structure of conductive and semiconductive materials. Developed in 1981 by Gerd Binnig and Heinrich Rohrer, STM revolutionized nanotechnology by providing atomic-scale resolution imaging. The principle of STM relies on quantum tunneling, where a sharp conductive tip is brought very close to a sample surface, typically within a few angstroms. When a voltage is applied between the tip and the sample, electrons tunnel through the vacuum gap, producing a measurable current that is sensitive to the distance between the tip and the surface atoms.

STM can operate in various modes, including constant current mode—where the tip height is adjusted to maintain a constant tunneling current to generate topographical images—and constant height mode—where the tip height remains fixed while variations in tunneling current reveal surface features. The technique is widely used to investigate surface topography, electronic properties, and atomic arrangements of materials such as metals, semiconductors, and molecules.

Due to its high spatial resolution, STM has applications in material science, nanotechnology, and surface chemistry, aiding in the manipulation of individual atoms and molecules. Limitations include the necessity for conductive samples and operation under ultra-high vacuum and low temperature conditions to achieve optimal resolution. Despite these constraints, STM remains a fundamental tool for nanoscale imaging and analysis, providing critical insights into atomic-scale phenomena.