Yuav ua li cas yog ib tug semiconductor? kuj semiconductor

Yuav ua li cas yog ib tug semiconductor khoom? Yuav ua li cas yog nws cov nta? Yuav ua li cas yog lub physics ntawm semiconductors? Raws li lawv ua? Yuav ua li cas yog lub conductivity ntawm semiconductors? Yuav ua li cas yog lub cev cwj pwm lawv muaj?

Yuav ua li cas yog hu ua semiconductors?

Nws yog hais txog crystalline ntaub ntawv uas tsis kev hluav taws xob kom zoo, raws li ua hlau. Tsis tau no daim duab yog zoo dua yog insulators. Cov yam ntxwv yog vim tus xov tooj ntawm mobile muaj. Yog hais tias peb xav txog, nyob rau hauv Feem ntau, muaj tshwm sim ib tug muaj zog Symptoms rau lub nuclei. Txawm li cas los, thaum muab nyob rau hauv ib tug neeg xyuas pib ob peb atoms, piv txwv li, antimony, uas muaj ib tug dhau heev lawm ntawm electrons, qhov no txoj hauj lwm yuav raug kho. Thaum uas siv cov indium npaj ntsiab nrog ib tug zoo xwb. Tag nrho cov khoom no dav siv nyob rau hauv transistors - tshwj xeeb pab kiag li lawm, uas tej zaum yuav txhim khu, thaiv los yog kis tau ib tug tam sim no nyob rau hauv ib tug coj xwb. Yog hais tias peb xav txog qhov NPN-hom caij, nws yuav tsum muaj cai muaj nuj nqis ntxiv zog rau lub luag hauj lwm uas yog tshwj xeeb yog ib qho tseem ceeb nyob rau hauv cov kis ntawm muaj zog Pib ntsais koj teeb.

Tsim nta uas muaj electrically semi-conductors

Conductors muaj ib tug ntau dawb electrons. Insulators lawv tsis yog muaj. Semiconductors thiab kuj muaj ib qhov nqi ntawm free electrons thiab kis nrog ib tug zoo xwb, uas yog npaj rau cov txais lub liberated hais. Thiab feem ntau cov tseem ceeb - lawv tag nrho cov nqa ib tug hluav taws xob tam sim no. Xam tias yog yav tas los NPN-hom transistor - tsis tau ib semiconductor caij. Yog li ntawd, muaj ntau ntau cov PNP-transistors thiab diodes.

Yog hais tias peb tham txog qhov kawg luv luv, nws yog lub caij uas yuav kis Pib ntsais koj teeb nyob rau hauv ib tug coj xwb. Tsis tas li ntawd, lub diode yuav hloov AC rau DC. Yuav ua li cas yog lub mechanism ntawm no transformation? Thiab yog vim li cas nws tsiv nyob rau hauv ib tug xwb? Txawm li cas los ntawm qhov muaj yog ib tug tam sim no, electrons thiab kis tau los yog tawg, los yog mus rau pem hauv ntej. Nyob rau hauv rooj plaub thawj vim lub zog deb pub mov yog tu ncua, thiab yog li ntawd yuav kis tau nqa tsis zoo voltage nyob rau hauv tsuas yog ib qho kev taw qhia, i.e. lub conductivity ntawm semiconductors yog unilateral. Tom qab tag nrho cov, tam sim no yuav kis tau yog hais tias qhov constituent hais yog ze rau ntawm. Thiab qhov no yog tau yog hais tias tam sim no mov nyob rau hauv ib tes. Cov no yog cov hom ntawm semiconductors ua ib ke thiab yuav siv tau nyob rau lub caij.

band qauv

Hluav taws xob cov thiab kho qhov muag khoom ntawm conductors txuam nrog lub fact tias, thaum sau lub zog theem ntawm electrons yog cais los ntawm cov tau xeev ntawm lub bandgap. Yuav ua li cas yog nws nta? Lub fact tias yog tsis muaj bandgap zog. Nrog impurities thiab yam ntxwv tsis xws luag nws yuav raug hloov. Dua tag nrho band hu ua valence. Raws li los ntawm ib tug daws teeb meem, tab sis tas. Nws yog hu ua tus conduction band. Physics ntawm semiconductors - ib tug heev interesting lub npe, thiab nyob rau hauv lub moj khaum ntawm tsab xov xwm nws yog zoo them.

lub xeev ntawm cov electrons

Nws yuav siv cov tswv yim xws li tus naj npawb ntawm tso cai band thiab cov quasi-momentum. Tus qauv yog txiav txim los ntawm tus thawj dispersion. Nws hais tias nyob rau hauv nws muaj feem xyuam rau lub zog dependence ntawm lub quasimomentum. Yog li, yog hais tias tus valence band yog kiag li lawm ua tus sau los ntawm electrons (uas nqa ib tug xwb nyob rau hauv ib tug semiconductor), peb hais tias muaj yog tsis muaj elementary excitations. Yog hais tias rau ib co yog vim li cas, tus hais tsis yog, nws txhais tau hais tias yog ib tug zoo them quasiparticle - dhau los yog qhov. Lawv yog cov them nyiaj nqa nyob rau hauv semiconductors nyob rau hauv lub valence band.

degenerate tsam

Lub valence band nyob rau hauv ib tug raug xyuas pib yog sixfold degenerate. Qhov no yog tsis suav cov spin-orbit sis thiab tsuas yog thaum tus siv lead ua momentum yog pes tsawg. Nws yuav cleaved nyob rau hauv tib yam kev mob rau lub doubly thiab fourfold degenerate band. Lub zog yov nruab nrab ntawm lawv yog hu ua lub zog ntawm cov spin-orbit splitting.

Impurities thiab tsis xws luag nyob rau hauv semiconductors

Lawv yuav ua tau electrically tsaug zog los yog kom nquag plias. Siv cov thawj tso cai rau koj kom tau nyob rau hauv semiconductors zoo los yog tsis zoo xwb, uas muaj peev xwm yuav pab txhawb los ntawm cov emergence ntawm ib lub qhov nyob rau hauv lub valence band los yog ib tug electron nyob rau hauv lub conduction band. Tsis voos impurities yog nruab nrab, thiab lawv muaj kuj me me cawv rau cov tshuab hluav taws xob zog. Ntxiv mus, nws feem ntau yuav tseem ceeb yog lub valence uas muaj atoms uas coj ib feem nyob rau hauv tus nqi hloov tus txheej txheem, thiab cov qauv ntawm cov qhov siv lead ua ntxaij ntoo.

Nyob ntawm seb lub hom thiab cov nyiaj uas impurities yuav hloov thiab tus piv ntawm tus xov tooj ntawm qhov thiab electrons. Yog li ntawd, semiconductor ntaub ntawv yuav tsum tau ua tib zoo xaiv mus cuag tej yam tshwm sim. Qhov no yog preceded los ntawm ib tug loj tus naj npawb ntawm suav, thiab tom qab lub thwmsim. Hais tias feem ntau cov hu ua feem ntau muaj, yog haiv neeg tsawg.

Dosed kev taw qhia ntawm impurities mus rau hauv lub semiconductor ntaus ntawv tso cai kom muab tau cov kev kawm lub zog. Tsis xws luag nyob rau hauv semiconductors kuj yuav tsaug zog los yog active hluav taws xob mob. Tseem ceeb no yog lub dislocation, interstitial atom thiab ib tug tsis txaus. Kua thiab noncrystalline conductors hnov mob impurities txawv dua li crystalline. Qhov uas tsis muaj ib tug nruj heev qauv nws thiaj li tau nyob rau hauv dab tsi tsiv lub atom acquires ib tug txawv valence. Nws yuav ua tau txawv los ntawm ib tug uas nws yog Ameslikas imbues lawv ties. Atom yuav unprofitable muab los yog muab lub electron. Nyob rau hauv xws li ib tug cov ntaub ntawv, nws yuav tsaug zog thiab, yog li ntawd, lub impurity semiconductors muaj ntau dua yuav tsis ua hauj lwm. Qhov no ua rau lub fact tias nws yog tsis yooj yim sua los mus hloov lub conductivity hom los ntawm doping thiab los ua, piv txwv li, p-n-hlws ris.

Ib txhia amorphous semiconductors yuav hloov tau lawv lub tshuab hluav taws xob zog nyob rau hauv tus ntawm doping. Tab sis nws khoom lawv mus rau ib tug npaum li cas lesser twg rau crystalline. Neeg rau doping amorphous ntsiab yuav kho los ntawm cov zauv. Thaum kawg, nws yuav tsum tau hais tias vim yog qhov ntev thiab zog ua hauj lwm impurity semiconductors cuaj kaum pib ib tug xov tooj ntawm cov yam ntxwv zoo tau.

Txheeb cais ntawm electrons nyob rau hauv lub semiconductor

Thaum muaj ib tug thermodynamic equilibrium, tus xov tooj ntawm qhov thiab electrons yog txiav txim heev dua lwm yam los ntawm qhov kub ntawm lub band qauv tsis thiab lub concentration ntawm electrically active impurities. Thaum tus piv yog xam, nws yog ntseeg hais tias ib co ntawm cov hais yuav tsum nyob rau hauv lub conduction band (nyob rau hauv lub acceptor los yog pub theem). Yog tseem coj mus rau hauv tus account lub fact tias feem ua tau tawm hauv ib ncig ntawm lub valence, thiab muaj tsim khoob.

conductivity

Nyob rau hauv semiconductors, dua li electrons li xwb muaj peev xwm ua tau thiab ions. Tab sis lawv hluav taws xob conductivity nyob rau hauv feem ntau negligible. Lub tsuas ionic superprovodniki yuav ua rau ib qho kev zam. Lub semiconductors yog peb lub ntsiab electron hloov lwm lub tsev mechanism:

1. Lub ntsiab tsam. Nyob rau hauv cov ntaub ntawv no, lub electrons nyob rau hauv tsab ntawv tsa suab vim cov kev hloov ntawm nws lub zog nyob rau hauv ib tso cai cheeb tsam.
2. Hopping thauj ntawm ib ncig lub xeev.
3. Polaron.

exciton

Lub qhov thiab lub electron yuav tsim ib tug bound lub xeev. Nws yog hu ua Wannier-Mott. Nyob rau hauv cov ntaub ntawv no rau hauv lub photon zog, uas sib raug rau ib tug haum ntug ntog rau hauv qhov ntau ntawm cov coupling kev daws teeb meem. Nrog txaus siv ntawm lub teeb nyob rau hauv semiconductors yuav tsim ib tug tseem ceeb npaum li cas ntawm excitons. Nrog ib qho kev nce rau hauv lawv cov concentration Condense thiab daim ntawv electron-qhov kua.

Nplaim cov semiconductor

Cov lus qhia ob peb atomic khaubncaws sab nraud povtseg, uas yog nyob ze ntawm lub ciam ntawm lub ntaus ntawv. Deg zog sib txawv los ntawm tej. Lub xub ntiag ntawm cov khaubncaws sab nraud povtseg lov Translational symmetry ntawm tus siv lead ua. Qhov no ua rau cov thiaj li hu ua nto lub xeev thiab polaritons. Tsim lub ntsiab ntawm lub caij nyoog kawg no, yuav tsum tau ntxiv rau qhia thiab hais txog lub kiv thiab vibrational tsis. Vim hais tias ntawm nws cov tshuaj ua si nkaum me me nto txheej sab nraum ntawm molecules los yog atoms uas tau raug adsorbed los ntawm cov ib puag ncig. Lawv kuj txiav txim lub zog ntawm cov ob peb atomic khaubncaws sab nraud povtseg. Qhov zoo ces, tus creation ntawm ultra-high nqus technology, nyob rau hauv uas yog semiconductor Cheebtsam, tso cai rau kom muab tau thiab muaj rau ob peb teev, huv si nto, uas zoo muaj feem xyuam rau qhov zoo ntawm cov khoom.

Semiconductor. Kub muaj feem xyuam rau cov kuj

Thaum tus kub ntawm cov hlau nce, thiab tsub kom lawv tsis kam. Nrog semiconductors, tus txheem no yeej muaj tseeb - nyob rau hauv tib tej yam kev mob, qhov kev xaiv no lawv yuav txo. Tus taw tes ntawm no yog hais tias qhov hluav taws xob conductivity nyob rau hauv tej ntaub ntawv (thiab qhov no yam ntxwv inversely xwm yeem mus rau kuj) yog nyob ntawm seb tus nqi tam sim no muaj yog, nyob rau cov kev ceev ntawm lub zog nyob rau hauv lub hluav taws xob field, thiab ntawm lawv tus xov tooj nyob rau hauv ib chav tsev ntim ntawm cov ntaub ntawv uas.

Lub semiconductor ntsiab tsub kom raws li cov kub tsub kom lub concentration ntawm hais, li no ua lub thermal conductivity thiab cov kuj tsawg. Koj muaj peev xwm mus saib qhov no nyob rau hauv lub xub ntiag ntawm tej yam yooj yim txheej hluas physicist thiab qhov tsim nyog cov ntaub ntawv uas - silicon los yog germanium, kuj yuav raug muab thiab ua los ntawm ib tug semiconductor lawv. Ib qho kev nce nyob rau hauv kub yuav txo lawv tsis kam. Yuav kom tau soj ntsuam xyuas no, koj yuav tsum Tshuag nyob rau ntsuas seev uas yuav saib tag nrho cov kev hloov. Qhov no yog feem ntau rooj plaub. Cia saib ib tug ob peb ntawm tej embodiments.

Kuj thiab electrostatic ionization

Qhov no yog vim tunneling ntawm electrons dua los ntawm ib tug nqaim heev barrier uas muab kwv yees li ib puas ntawm micrometer. Nws yog situated ntawm cov npoo ntawm lub zog bands. Nws zoo li yog xwb tau thaum dabtsi yog khoov zog bands, uas tshwm sim xwb nyob rau hauv tus ntawm ib tug muaj zog hluav taws xob field. Thaum tunneling tshwm sim (uas yog ib tug quantum txhua yam nyhuv), cov electrons kis tau los ntawm lub peev xwm teeb meem yog nqaim, thiab nws tsis hloov lawv lub zog. Qhov no entails ib qho kev nce rau hauv lub concentration xwb muaj, thiab nyob rau hauv ob qho tib si aav: lub conduction thiab valence. Yog hais tias tus txheej txheem yog los tsim lub electrostatic ionization, yuav muaj ib tug rhuav tshem ntawm lub semiconductor qhov. Thaum lub sij hawm tus txheej txheem no nws yuav hloov cov kuj ntawm lub semiconductor. Nws yog reversible, thiab sai li sai raws li lub hluav taws xob field yog muab tua, tag nrho cov dab raug txum tim rov.

Kuj thiab tej yam ionization

Nyob rau hauv cov ntaub ntawv no, lub qhov thiab cov electrons yog ceev kom txog thaum kuaj dawb txoj kev nyob rau hauv tus ntawm ib tug muaj zog hluav taws xob field mus rau qhov tseem ceeb uas ua rau kom ionization ntawm cov atoms thiab cov kev sib tawg ntawm ib qho ntawm lub covalent bonds (thawj los yog impurity atom). Impact ionization tshwm sim zoo li ib tug avalanche thiab nws avalanche multiply xwb muaj. Yog li tus tshiab khiv tsim qhov thiab electrons ceev los ntawm lub fais tam sim no. Tus tam sim no tus nqi nyob rau hauv zaum kawg tshwm sim yog multiplied los ntawm ib tug coefficient ntawm tej yam ionization, uas yog tus naj npawb ntawm electron-qhov officers uas tsim nyob rau ib qho ntawm tus nqi cov cab kuj txoj kev ya. Cov kev loj hlob ntawm tus txheej txheem no nws thiaj li ua rau yus semiconductor avalanche neej puas. Lub kuj semiconductors yog tseem hloov, tab sis, raws li nyob rau hauv cov ntaub ntawv ntawm qhov lub neej puas, reversible.

Kev siv cov semiconductors nyob rau hauv kev xyaum

Cov kev tseem ceeb ntawm cov ntsiab yuav tsum tau muab sau tseg nyob rau hauv computer technology. Yuav luag tsis muaj cov tsis ntseeg tias koj yuav tsis yuav txaus siab nyob rau hauv cov nqe lus nug ntawm yog dab tsi lub semiconductors, yog hais tias tsis muaj lub siab mus ntawm nws tus kheej tsa cov kev kawm uas lawv siv. Nws yog tsis yooj yim sua xav txog tej yam lub chaw ua hauj lwm uas niaj hnub tub yees, TV poob lawm, computer saib tsis semiconductors. Yuav tsis tau ua tsis muaj lawv, thiab tshaj tsheb engineering. Lawv kuj siv nyob rau hauv chaw ua dav hlua thiab qhov chaw technology. To taub dab tsi semiconductors yog, yuav ua li cas ib qho tseem ceeb lawv yog? Ntawm cov hoob kawm, peb tsis tau hais tias nws tsuas yog lub ntsiab tseem ceeb ntawm peb cov kev vam meej, tab sis kuj underestimate lawv yog tsis tsim nyog.

Kev siv cov semiconductors nyob rau hauv kev xyaum, vim ntau thiab ib tug xov tooj ntawm lwm yam, nyob rau hauv lawv lub thoob plaws ntawm cov ntaub ntawv los ntawm qhov uas lawv ua, thiab yooj yim ntawm kev thiab mus muab tau cov kev kawm ntawd, thiab lwm yam kev nta uas ua rau cov kev xaiv ntawm tus zaum uas ua hauj lwm nyob rau hauv lub tshuab hluav taws xob khoom, nres lawv.

xaus

Peb tau soj ntsuam nyob rau hauv kom meej li cas semiconductors, yuav ua li cas lawv ua hauj lwm. Lub hauv paus ntawm lawv tsis kam muab txoj cev thiab tshuaj dab. Thiab koj yuav pom tias qhov tseeb tsis muab raws li tau piav nyob rau hauv tsab xov xwm tag nrho to taub hais tias xws li semiconductors, rau tej yam yooj yim yog vim li cas hais tias kev kawm tsis tau txawm kawm peculiarities ntawm lawv ua hauj lwm mus txog thaum kawg. Tiam sis peb paub hais tias lawv yooj yim zog thiab cov yam ntxwv, uas tso cai rau peb mus muab lawv mus rau hauv xyaum. Yog li ntawd, koj muaj peev xwm nrhiav rau cov ntaub ntawv thiab semiconductors mus xyaum ua tej nrog lawv, ua tau ceev faj. Leej twg paub, tej zaum nyob rau hauv koj pw tsaug zog zoo kawg soj ntsuam?!