Tiêu đề elect lec 1-4 (basics to diode in ac ckt).pdf ✅

Najmus Sakib, BUET (EEE-14) ; WhatsApp: 01892777317 • Covalent bonds exist between Si atoms and they form a crystal structure. The image here shows the structure with all bonds intact. This is possible only at low temperatures. • As the temperature increases and more energy becomes available to the valence electrons, they break away leading to an increase in conductivity of the element. Intrinsic Semiconductors
Najmus Sakib, BUET (EEE-14) ; WhatsApp: 01892777317 • Now, the thermal energy ionizes only a few atoms. This ionization creates a vacancy in the bond. • When an electron, having charge –q, gets excited due to the thermal energy, it breaks free from the bond. • This leaves a vacancy there with effective charge +q. This vacancy with an effective positive electronic charge is a hole. • In intrinsic semiconductors, the number of free electrons is equal to the number of holes and is called the intrinsic carrier concentration. Intrinsic Semiconductors