Depletsioonitsooni

Depletsioonitsooni, often translated as depletion zone or depletion region, refers to a region within a semiconductor where mobile charge carriers (electrons and holes) have been swept away. This absence of free charge carriers creates an electrically neutral area, hence the term "depletion."

This phenomenon is fundamental to the operation of many semiconductor devices, most notably diodes and transistors. When a p-n junction is formed, the interface between p-type and n-type semiconductor materials, the inherent diffusion of charge carriers across the junction leads to the formation of a depletion zone. In a p-type material, holes diffuse into the n-type region, and in an n-type material, electrons diffuse into the p-type region. As these mobile carriers diffuse, they leave behind immobile ionized dopant atoms. These ionized atoms create an electric field within the depletion zone, which opposes further diffusion and establishes an equilibrium.

The width of the depletion zone is influenced by factors such as the doping concentrations of the semiconductor materials and the applied voltage across the junction. Applying a reverse bias to a p-n junction widens the depletion zone by actively pulling charge carriers away from the junction. Conversely, a forward bias narrows the depletion zone, allowing current to flow more easily. Understanding and controlling the depletion zone is crucial for designing and fabricating semiconductor devices with specific electrical characteristics.