Löcherkonzentration

Löcherkonzentration is the concentration of positive charge carriers (holes) in a semiconductor, commonly expressed as the number of holes per unit volume (e.g., cm^-3). It is a fundamental parameter for describing electrical behavior in p-type materials where acceptor impurities or thermal excitation create vacant electron states in the valence band that act as mobile positive carriers.

Under thermal equilibrium the hole concentration p is related to the electron concentration n by the mass action law n p = ni^2, where ni is the intrinsic carrier concentration. In doped semiconductors with full ionization of acceptors, the majority-hole concentration is approximately equal to the acceptor density (p ≈ NA). The minority-electron concentration is then n = ni^2 / p. The hole concentration depends strongly on temperature, doping level and the position of the Fermi level relative to the valence band; in non-equilibrium situations separate quasi-Fermi levels describe electrons and holes.

Löcherkonzentration directly influences conductivity and device behavior: electrical conductivity σ = q (p μp + n μn) and diffusion lengths, recombination rates and junction characteristics scale with carrier densities. It is commonly measured by Hall effect techniques, capacitance–voltage profiling, optical methods and conductivity measurements. Typical contexts for the term include semiconductor physics, device engineering and materials characterization, especially for silicon-based electronics and optoelectronic devices.