Mai yadda Intrinsic Semiconductor?

Zai Intrinsic Semiconductor shine ne?

Takaitaccen Intrinsic Semiconductor

Semiconductor shine mutanen da tsari shi na tare da mafi yawan kudin hanyar wani abu da mafi yawan kudin hanyar. Semiconductors masu kyawawan kimya, ya'ni muna jama'a, suna nufin Intrinsic Semiconductors ko Undoped Semiconductor ko i-type Semiconductor. Masu yawan in intrinsic semiconductors su Silicon (Si) da Germanium (Ge), wadanda suke cikin Group IV ta takaitaccen duka. Sunan atomic na Si da Ge shine 14 da 32, wanda yake bayyana configuration electronic shi domin 1s2 2s2 2p6 3s2 3p2 da 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2, har zuwa.

Duka Si da Ge suna da elektron ɗaya a kan karshen babbar, ko valence, shi. Wannan valence electrons suna da alaka da yadda semiconductors suke kudin hanyar.

Crystal lattice na Silicon (ko kuma Germanium) a biyu-dimension ana fahimtar Figure 1. A nan ana gani cewa har da elektron valence na atom na Si yana haɗa da elektron valence na atom na Si na makamfi don zabe covalent bond.

Ba a yi haɗa, ba intrinsic semiconductors bata suka da free charge carriers, wadanda su ke valence electrons. A 0K, band na valence ana kasa, kuma band na conduction ana ɗauki. Ba wani valence electron bata da energy da yake da kyau don haɓaka forbidden energy gap, wanda yake buƙace intrinsic semiconductors suke kudin hanyar a 0K.

Amma a tsari, thermal energy zai iya haɓaka wasu covalent bonds suke ɗauki, don haka za su faɗi free electrons kamar yadda ake nuna a Figure 3a. Electrons da aka fara suke haɓaka da energy da yake da kyau don haɓaka min band na valence zuwa band na conduction, wanda yake buƙace energy barrier (Figure 2b). A cikin wannan ingantacce, har da elektron yana rage hole a band na valence. Electrons da holes da aka fara hakan suka nufin intrinsic charge carriers, wadanda suke da alaka da yadda material na intrinsic semiconductor suke kudin hanyar.

Idan intrinsic semiconductors suke kudin hanyar a tsari, amma conductivity su ke ɗaya saboda wasu charge carriers. Idan temperature yana ɗauki, zai iya ɗauki wasu covalent bonds, don haka za su faɗi free electrons. Electrons waɗanda aka fara suke haɓaka min band na valence zuwa band na conduction, wanda yake ɗauki conductivity. Yawan electrons (ni) yana da damar yawan holes (pi) a cikin intrinsic semiconductor.

A yi electric field zuwa intrinsic semiconductor, za su iya ɗaukan electron-hole pairs suke ɗaukanci. A cikin wannan, electrons suke haɓaka min yanayin applied field, amma holes suke haɓaka min yanayin electric field kamar yadda ake nuna a Figure 3b. Haka na nufin cewa yanayin da electrons da holes suke haɓaka suke ɗaya. Saboda haka, idan electron na wani atom yana haɓaka min yanayin say, left, da rage hole a kan rike, electron na atom na makamfi yana haɓaka zuwa rike re by recombining with that hole. Amma a cikin hakan, yana rage hole ɗaya a kan rike. Wannan zai iya haɗa da movement of the holes (zuwa right side a cikin wannan misali) a cikin material na semiconductor. Waɗannan hukumomin, idan suke ɗaya a yanayin, suke ɗauki total flow of current zuwa semiconductor.

Mathematically, charge carrier densities a cikin intrinsic semiconductors suke nuna

A nan,

N c shine effective densities of states a cikin band na conduction.

Nv shine effective densities of states a cikin band na valence.

shine Boltzmann constant.

T shine temperature.

EF shine Fermi energy.

Ev na nufin level na valence band.

Ec na nufin level na conduction band.

shine Planck constant.

mh shine effective mass na hole.

me shine effective mass na electron.