polovodi

Polovodi are materials with electrical conductivity between that of metals and insulators. Their conductivity can be tuned by temperature, impurities, light, and electric fields, making them essential for modern electronics. The most common polovodi are crystalline silicon and germanium, though many compound semiconductors such as gallium arsenide and indium phosphide are used for specialized high-frequency and optoelectronic applications.

In intrinsic (undoped) semiconductors, a small number of charge carriers is thermally generated; conductivity increases with temperature. Doping introduces impurities that donate free carriers or create vacancies that act as carriers, giving rise to n-type and p-type materials. Donors add electrons; acceptors create holes. In n-type materials the majority carriers are electrons; in p-type, holes are majority.

Joining p-type and n-type materials forms a p-n junction, the fundamental building block of diodes, solar cells, and transistors. Diodes conduct current primarily in one direction, while transistors such as bipolar junction transistors and field-effect transistors amplify or switch signals. Modern electronics relies on large-scale integration of many semiconductor devices on silicon wafers.

Manufacturing involves crystal growth, wafer slicing, and defined doping through diffusion or ion implantation, followed by diffusion, annealing, and patterning using photolithography and deposition techniques. The industry shifted from germanium to silicon and, more recently, to compound and wide-bandgap materials for specialized power, radiofrequency, and optoelectronic devices.

Polovodi underpin technologies from microprocessors and memory to LEDs, lasers, solar cells, and sensors. Ongoing research aims to improve efficiency, reduce costs, and enable new functionalities such as flexible electronics and quantum devices.