Trägerdichte

Trägerdichte refers to the concentration of charge carriers within a material, typically a semiconductor. These charge carriers are fundamental particles that carry electric charge, and their most common forms are electrons and holes. Electrons are negatively charged particles found in the conduction band of a semiconductor, while holes are vacancies in the valence band that behave as positive charges.

The number of these charge carriers per unit volume defines the Trägerdichte. In intrinsic semiconductors, where no impurities have been added, the Trägerdichte is determined by the material's bandgap and temperature. In extrinsic semiconductors, which have been doped with impurities to increase the concentration of either electrons (n-type) or holes (p-type), the Trägerdichte is significantly influenced by the doping concentration.

A higher Trägerdichte generally leads to increased electrical conductivity in a material. This is because there are more mobile charge carriers available to participate in current flow when an electric field is applied. Conversely, a lower Trägerdichte results in lower conductivity. Understanding and controlling the Trägerdichte is crucial in the design and fabrication of semiconductor devices, such as transistors, diodes, and solar cells, as it directly impacts their electrical performance and functionality.