Mehrheitsladung

Mehrheitsladung is the term used in semiconductor physics to denote the dominant type of charge carrier in a material. In this context, the Mehrheitsladung refers to the carrier species present in the greater concentration, which largely governs electrical conduction. The concept is most commonly applied to doped semiconductors, where the balance between electrons and holes can be shifted away from the intrinsic 1:1 ratio.

In n-type semiconductors, electrons are the Mehrheitsladung, while holes are the minority carriers. In p-type semiconductors, holes are the Mehrheitsladung and electrons are the minority carriers. The dominance of the Mehrheitsladung is achieved through doping: donor atoms introduce extra electrons for n-type materials, and acceptor atoms create additional holes for p-type materials. The minority carrier concentration can be estimated from the intrinsic concentration and the level of doping.

Electrical conductivity in semiconductors depends on both carrier types, but the Mehrheitsladung typically provides the larger contribution to conduction. The conductivity can be expressed as σ = q (n μn + p μp), where n and p are the electron and hole concentrations, and μn and μp are their mobilities. Under ordinary conditions, the product of the Mehrheitsladung density and its mobility dominates, though minority carriers are crucial for many device functions.

Applications and implications: the concept helps explain the behavior of diodes, transistors, and other semiconductor devices, where the distribution of Mehrheitsladung and minority carriers determines diffusion, drift, and recombination processes. In junctions, the balance between majority and minority carriers shapes the space-charge region and device response to illumination or bias.

See also: minority carrier, doping, semiconductor conductivity, p-n junction.