dopanttiatomien

Dopanttiatomit, or dopant atoms, are impurity atoms introduced into a semiconductor crystal lattice to alter its electrical conductivity. This process is known as doping. Pure semiconductors, like silicon or germanium, have a limited number of free charge carriers, making them poor conductors at room temperature. By intentionally adding dopant atoms, the number of free electrons or holes can be significantly increased.

There are two main types of dopants: n-type and p-type. N-type dopants are elements with more valence electrons than the semiconductor material itself. For example, in silicon (which has four valence electrons), adding phosphorus or arsenic (which have five valence electrons) introduces extra free electrons. These excess electrons become the majority charge carriers, leading to an n-type semiconductor.

P-type dopants, conversely, have fewer valence electrons than the semiconductor. Adding elements like boron or gallium (which have three valence electrons) to silicon creates "holes," which are essentially vacancies where an electron should be. These holes act as positive charge carriers, and in p-type semiconductors, holes are the majority charge carriers. The controlled introduction of dopant atoms is fundamental to the fabrication of semiconductor devices such as diodes, transistors, and integrated circuits, enabling their specific electronic functions.