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Zoltlelmdvet`~`tp

Elmefztvci Fzicmct`lm cmd Czzi`ect`lm

hp

Ucxctop Acmmcm G

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Zoltlelmdvet`~`tp `u cm lzt`eci cmd fifetx`eci zofmlkfmlm `m wo`eo c

kctfx`ci hfelkfu klxf fifetx`eciip elmdvet`~f dvf tl tof chulxzt`lm ln

fifetxlkcgmft e xcd`ct`lm uveo cu ~`u`hif i`got vitxc~`lift i`got mnxcxfd i`got

lx gckkc xcd`ct`lm-

Zx`me`zif

Wofm i`got `u chulxhfd hp c kctfx`ci uveo cu c ufk`elmdvetlx tof mvkhfx ln

nxff fifetxlmu cmd fifetxlm olifu eocmgfu cmd xc`ufu tu fifetx`eci elmdvet`~`tp-

Tl ecvuf fe`tct`lm tof i`got toct utx`afu tof ufk`elmdvetlx kvut oc~f fmlvgo

fmfxgp tl xc`uf fifetxlmu cexluu tof hcmd gcz lx tl fe`tf tof `kzvx`t`fu

w`to`m tof hcmd gcz- Wofm c h`cu ~litcgf cmd c ilcd xfu`utlx cxf vufd `m ufx`fu

w`to tof ufk`elmdvetlx c ~litcgf dxlz cexluu tof ilcd xfu`utlxu ecm hf

kfcuvxfd wofm tof eocmgf `m fifetx`eci elmdvet`~`tp ln tof kctfx`ci ~cx`fu tof

evxxfmt nilw`mg toxlvgo tof e`xev`t-

Eicuu`e fckzifu ln zoltlelmdvet`~f kctfx`ciu meivdf tof elmdvet`~f

zlipkfx zlip~`mpiecxhcrlif vufd ftfmu`~fip `m zoltlelzp`mg /fxlgxczop)1

ifcd uvin`df vufd m mnxcxfd dftfet`lm czzi`ect`lmu uveo cu tof V-U-

U`dfw`mdfx cmd Xvuu`cm Ctlii ofct+uffa`mg k`uu`ifu1 cmd ufifm`vk fkzilpfd

`m fcxip tfif~`u`lm cmd fxlgxczop-

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@n Fg hf tof k`m`kvk hcmd gcz `m c ufk`elmdvet`mg kctfx`ci tofm tof ilmgfut

wc~fifmgto wo`eo kcp ecvuf to`u fnnfet `u

;oe,Fg

tof fifetx`eci elmdvet`~`tp ln cm `muvictlx lx c ufk`elmdvetlx `u g`~fm hp

; f/m-m ! z-z)

wofxf `u tof elmdvet`~`tp ln tof kctfx`ci m cmd z cxf tof fifetxlm cmd olif

elmefmtfxct`lm cmd m cmdz cxf tof fifetxlm cmd olif klh`i`t`fu-

@m c olklgfmflvu kctfx`ci wofxf tof fifetxlm cmd olif elmefmtfxct`lmu cxf

vm`nlxk tof x`uf `m elmdvet`~`tp `u g`~fm hp

; f/m-m ! z-z)

@m @muvictlxu tof ~civf ln m cmd z cxf icxgf elkzcxfd tl tof elxxfuzlmd`mg

tl nxff ecxx`fx dfmu`tp `m tof dcxa wofxfcu nlx ufk`elmdvetlxu to`u x`uf `u

~fxp ukcii elkzcxfd tl dcxa ecxx`fx dfmu`tp-

@m c mlm+olklgfmflvu kctfx`ci `m wo`eo m cmd z cxf mlt vm`nlxk tof

`mexfcuf m zoltlelmdvet`~`tp u dvf tl mexfcuf m tof ~civf ln z cmd

m- @m tofuf kctfx`ciu tof x`uf `m elmdvet`~`tp ecm hf fzxfuufd cu

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; f/m-m !z-z)

Zoltlufmu`t`~`tp

'Zoltlufmu`t`~`tp' `u tof cklvmt tl wo`eo cmd lhbfet xfcetu vzlm

xfef`~`mg zoltlmu fuzfe`ciip ~`u`hif i`got-

U ; zo ,d

wofxf zo ; tltci +d

wofxf zo `u tof zoltlelmdvet`~`tp cmd d `u tof dcxa elmdvet`~`tp-

Tof Uzfetxci Xfuzlmuf

Tof ~cx`ct`lm ln zoltlelmdvet`~`tp w`to zoltlm fmfxgp `u amlwm cu uzfetxci

xfuzlmuf- Tof kc`kvk ~civf ln zoltlevxxfmt elxxfuzlmdu tl hcmd gcz

fmfxgp cmd uzfetxci xfuzlmuf- Tof fmfxgp xcmgfu nxlk 5-7 f^ nlx RmU tl :-8 f^

nlx ellifd ZhUf-

Uzfetxci xfuzlmuf nlx zoltl elmdvet`mg kctfx`ciu-

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Uzffd ln Xfuzlmuf

@t `u tof xctf ln tof eocmgf `m zoltlelmdvet`~`tp w`to eocmgf `m zoltl

fe`tct`lm mtfmu`tp- @t u utvd`fd hp uw`teo`mg lnn c utfcdp zoltl fe`tct`lm`mtfmu`tp- Nlx kctfx`ciu w`to fzlmfmt`ci dfecp tof zoltlevxxfmt xfceofu tof

dcxa evxxfmt ~fxp sv`eaip cmd nlx kctfx`ciu w`to mlm fzlmfmt`ci dfecp tof

dfecp ln zoltlevxxfmt tcafu c ilmgfx t`kf tl xfceo dcxa evxxfmt-

Zoltlelmdvet`~f Kctfx`ciu

Tof Xfsv`xfd Eocxcetfx`ut`eu ln c Zoltlelmdvet`~f kctfx`ciu cxf

O`go uzfetxci ufmu`t`~`tp `m tof wc~fifmgto xfg`lm ln`mtfxfut

O`gofx svcmtvk fnn`e`fmep O`gofx zoltlelmdvet`~f gc`m O`gofx uzffd ln xfuzlmuf cmd ifuufx ml`uf

Ulkf ln tof mltchif zoltlelmdvet`~f kctfx`ciu toct cxf hf`mg vufd w`dfip m

elmtfkzlxcxp wlxid cxf EdU EdUf ZhU @mUh Kfxevxp Ecdk`vk Tfiivx`df

/OgEd3+Tf)-

Ecdk`vk uvizo`df /EdU) cmd Ecdk`vk Ufifm`df /EdUf)

Tofp cxf ilw elut kctfx`ciu cmd cxf vufd cu ~`u`hif xcd`ct`lm ufmulxu hfecvuf

tofp cxf o`goip ufmu`t`~f/3L5 tl 3:4)- Dvf tl tof`x o`go Ufmu`t`~`tp tof

xfuzlmuf t`kf utxlmgip dfzfmdu lm tof iivk`mct`lm if~fi md`ect`mg tof

f`utfmef ln txczu-

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Ifcd Uvizo`df /ZhU)

Tofuf dftfetlxu cxf vufd tl dftfet mfcx mnxcxfd m tof wc~fifmgto xcmgf nxlk

3 k tl 5-4 k- Tof klut ufmu`t`~f xfg`lm ln to`u kctfx`ci `u 8 w`to c tpz`ecixfuzlmuf t`kf ln 8:: u-

@md`vk Cmt`klmp /@mUh)

Tofuf dftfe tlxu cxf nlxkfd nxlk u`mgif exputciu w`to ilw `kzfdcmef /6:)-

@t ecm hf vufd vztl 7k w`to c xfuzlmuf t`kf ln 6: mu- @t ecm hf lzfxctfd ct

xllk tfkzfxctvxf1 olwf~fx lmf ecm oc~f cm `kzxl~fd ml`uf xfdvet`lm ct

ilw tfkzfxctvxfu uveo cu i`sv`d m`txlgfm tfkzfxctvxf-

Kfxevxp Ecdk`vk Tfiivx`df

@t `u c elkh`mct`lm ln ufk` kftci OgTf cmd ufk`elmdvetlx EdTf ciilp

w`to c ~cxp`mg hcmd gcz ln :+3-4 f^ tof hcmd gcz ln zvxf EdTf-- Tof

ufmu`t`~`t`fu ln tofuf dftfetlxu i`f `m tof xcmgf nxlk 6 tl 34 k- Tof gc`m ln

tofuf `u chlvt 6:: wo`eo ecm hf nvxtofx `mexfcufd ct ilw tfkzfxctvxf cmd

ilw `iivk`mct`lmu dvf tl tof fnnfet ln txczu-

Czzi`ect`lmu

c- Zoltld`ldf2C zoltld`ldf `u c tpzf ln zoltl dftfetlx eczchif ln elm~fxt`mg i`got `mtl f`tofx

evxxfmt lx ~litcgf dfzfmd`mg vzlm tof kldf ln lzfxct`lm- Tof elkklm

txcd`t`lmci ulicx efii vufd tl gfmfxctf fifetx`e ulicx zlwfx `u c icxgf cxfczoltld`ldf-

Zoltld`ldfu cxf u`k`icx tl xfgvicx ufk`elmdvetlx d`ldfu fefzt toct tofp kcp

hf f`tofx fzlufd /tl dftfet ~cevvk V^ lx _+xcpu) lx zceacgfd w`to c

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w`mdlw lx lzt`eci n`hfx elmmfet`lm tl ciilw i`got tl xfceo tof ufmu`t`~f zcxt ln

tof df~`ef- Kcmp d`ldfu dfu`gmfd nlx vuf uzfe`n`eciip cu c zoltld`ldf vuf c

Z@M bvmet`lm xctofx tocm c z+m bvmet`lm tl `mexfcuf tof uzffd ln xfuzlmuf- C

zoltld`ldf u dfu`gmfd tl lzfxctf m xf~fxuf h`cu-

C zoltld`ldf `u c z+m bvmet`lm lx Z@M utxvetvxf- Wofm c zoltlm ln uvnn`e`fmt

fmfxgp utx`afu tof d`ldf `t fe`tfu cm fifetxlm tofxfhp exfct`mg c nxff fifetxlm

/cmd c zlu`t`~fip eocxgfd fifetxlm olif)- To`u kfeocm`uk `u ciul amlwm cu tof

`mmfx zoltlfifetx`e fnnfet- @n tof chulxzt`lm leevxu m tof bvmet`lm'u dfzift`lm

xfg`lm lx lmf d`nnvu`lm ifmgto cwcp nxlk `t tofuf ecxx`fxu cxf uwfzt nxlk tof

bvmet`lm hp tof hv`it+`m n`fid ln tof dfzift`lm xfg`lm- Tovu olifu kl~f tlwcxd

tof cmldf cmd fifetxlmu tlwcxd tof ectoldf cmd c zoltlevxxfmt u zxldvefd-

To`u zoltlevxxfmt `u tof uvk ln hlto tof dcxa evxxfmt /w`tolvt i`got) cmd tofi`got evxxfmt ul tof dcxa evxxfmt kvut hf k`m`k`rfd tl fmocmef tof

ufmu`t`~`tp ln tof df~`ef-

Zoltl~litc`e kldf2

Wofm vufd `m rfxl h`cu lx zoltl~litc`e kldf tof nilw ln zoltlevxxfmt lvt ln

tof df~`ef `u xfutx`etfd cmd c ~litcgf hv`idu vz- To`u kldf fzil`tu tof

zoltl~litc`e fnnfet wo`eo u tof hcu`u nlx ulicx efiiu c txcd`t`lmci ulicx efii `u

bvut c icxgf cxfc zoltld`ldf-

Zoltlelmdvet`~f kldf2

@m to`u kldf tof d`ldf u lntfm xf~fxuf h`cufd /w`to tof ectoldf zlu`t`~f)

dxckct`eciip xfdve`mg tof xfuzlmuf t`kf ct tof fzfmuf ln `mexfcufd ml`uf-

To`u `mexfcufu tof w`dto ln tof dfzift`lm icpfx wo`eo dfexfcufu tof bvmet`lm'u

eczce`tcmef xfuvit`mg `m ncutfx xfuzlmuf t`kfu- Tof xf~fxuf h`cu `mdvefu lmip c

ukcii cklvmt ln evxxfmt /amlwm cu uctvxct`lm lx hcea evxxfmt) cilmg `tu

d`xfet`lm wo`if tof zoltlevxxfmt xfkc`mu ~`xtvciip tof uckf- Nlx c g`~fm

uzfetxci d`utx`hvt`lm tof zoltlevxxfmt u i`mfcxip zxlzlxt`lmci tl tof

`iivk`mcmef /cmd tl tof xxcd`cmef)-

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Citolvgo to`u kldf `u ncutfx tof zoltlelmdvet`~f kldf tfmdu tl fo`h`t klxf

fifetxlm`e ml`uf-Qe`tct`lm mffdfd[ Tof ifcacgf evxxfmt ln c glld Z@M d`ldf u

ul ilw /93 mC) toct tof BlomulmMpsv`ut ml`uf ln tof ilcd xfu`utcmef `m c

tpz`eci e`xev`t lntfm dlk`mctfu-

Czzi`ect`lmu

Z+M zoltld`ldfu cxf vufd m u`k`icx czzi`ect`lmu tl ltofx zoltl dftfetlxu

uveo cu zoltlelmdvetlxu eocxgf+elvzifd df~`efu cmd zoltlkvit`zi`fx tvhfu-

Tofp kcp hf vufd tl gfmfxctf cm lvtzvt wo`eo `u dfzfmdfmt vzlm tof

`iivk`mct`lm /cmcilg1 nlx kfcuvxfkfmt cmd tof i`af) lx tl eocmgf tof utctf ln

e`xev`txp /d`g`tci1 f`tofx nlx elmtxli cmd uw`teo`mg lx d`g`tci u`gmci zxlefuu`mg)-

Zoltld`ldfu cxf vufd m elmuvkfx fifetxlm`eu df~`efu uveo cu elkzcet d`ue

zicpfxu uklaf dftfetlxu cmd tof xfef`~fxu nlx `mnxcxfd xfkltf elmtxli

df~`efu vufd tl elmtxli fsv`zkfmt nxlk tfif~`u`lmu tl c`x elmd`t`lmfxu- Nlx

kcmp czzi`ect`lmu f`tofx zoltld`ldfu lx zoltlelmdvetlxu kcp hf vufd-

F`tofx tpzf ln zoltl ufmulx kcp hf vufd nlx i`got kfcuvxfkfmt cu `m eckfxc

i`got kftfxu lx tl xfuzlmd tl i`got if~fiu cu `m uw`teo`mg lm utxfft i`got`mg

cntfx dcxa-

Zoltld`ldfu cxf lntfm vufd nlx ceevxctf kfcuvxfkfmt ln i`got mtfmu`tp m

ue`fmef cmd `mdvutxp- Tofp gfmfxciip oc~f c klxf i`mfcx xfuzlmuf tocm

zoltlelmdvetlxu-

Tofp cxf ciul w`dfip vufd `m ~cx`lvu kfd`eci czzi`ect`lmu uveo cu dftfetlxu

nlx elkzvtfd tlklgxczop /elvzifd w`to ue`mt`iictlxu) mutxvkfmtu tl cmciprf

uckzifu /`kkvmlcuucp) cmd zviuf l`kftfxu-

Z+M zoltld`ldfu cxf mlt vufd tl kfcuvxf ftxfkfip ilw i`got `mtfmu`t`fu-@mutfcd `n o`go ufmu`t`~`tp `u mffdfd c~cicmeof zoltld`ldfu `mtfmu`n`fd

eocxgf+elvzifd df~`efu lx zoltlkvit`zi`fx tvhfu cxf vufd nlx czzi`ect`lmu

uveo cu cutxlmlkp uzfetxluelzp m`got ~`u`lm fsv`zkfmt cmd icufx xcmgf

n`md`mg-

h- Zoltl~litc`e efii/ Ulicx Efii)

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Hfesvcxfi `m 3?50 d`uel~fxfd toct wofm c zc`x ln fifetxldfu `u

`kkfxufd `m cm fifetxliptf cmd i`got `u ciilwfd tl `me`dfmt lm lmf ln

tofk c zltfmt`ci d`nnfxfmef `u exfctfd hftwffm fifetxldfu - To`uzofmlkfmlm `u eciifd zoltl~litc`e fnnfet- Df~`ef hcufd lm to`u fnnfet

cxf amlwm cu Zoltl+^litc`e efii - To`u zoltl~litc`e efii cxf tof df~`efu `m

wo`eo i`got fmfxgp `u vuf tl exfctf c zltfmt`ci d`nnfxfmef ul df~filzfd `u

d`xfetip zxlzlxt`lmci tl tof nxfsvfmep cmd mtfmu`tp ln `me`dfmt i`got-

Vufu

Lzfxct`lm ln xficpu Zoltlgxczo`e fzluvxf D`xfet xfcd`mg iivk`mct`lm kftxl-

e- Zoltlelmdvet`~f efii /lx Zoltlxfu`utlx)

C zoltlxfu`utlx lx i`got dfzfmdfmt xfu`utlx /IDX) `u

c xfu`utlx woluf xfu`utcmef dfexfcufu w`to `mexfcu`mg `me`dfmt i`got `mtfmu`tp1

`m ltofx wlxdu `t fo`h`tuzoltlelmdvet`~`tp-

http://en.wikipedia.org/wiki/Resistorhttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Photoconductivityhttp://en.wikipedia.org/wiki/Photoconductivityhttp://en.wikipedia.org/wiki/Photoconductivityhttp://en.wikipedia.org/wiki/Photoconductivityhttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Resistor

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Zx`me`zif

C zoltlxfu`utlx `u kcdf ln c o`go xfu`utcmef ufk`elmdvetlx- @n i`got ncii`mg lm

tof df~`ef `u ln o`go fmlvgo nxfsvfmep zoltlmu chulxhfd hp tof

ufk`elmdvetlx g`~f hlvmd fifetxlmu fmlvgo fmfxgp tl bvkz `mtl

tof elmdvet`lm hcmd- Tof xfuvit`mg nxff fifetxlm /cmd tu olif zcxtmfx)elmdvet fifetx`e`tp tofxfhp ilwfx`mg xfu`utcmef-

Uafteo ln Zoltlelmdvet`~f df~`ef

upkhli ln zoltl xfu`utlx

C zoltlfifetx`e df~`ef ecm hf f`tofx mtx`mu`e lx ftx`mu`e- Cm mtx`mu`e

ufk`elmdvetlx ocu tu lwm eocxgf ecxx`fxu cmd `u mlt cm fnn`e`fmt

ufk`elmdvetlx nlx fckzif u`i`elm- @m mtx`mu`e df~`efu tof lmip c~c`ichif

fifetxlmu cxf `m tof ~cifmef hcmd cmd ofmef tof zoltlm kvut oc~f fmlvgofmfxgp tl fe`tf tof fifetxlm cexluu tof fmt`xf hcmdgcz- Ftx`mu`e df~`efu oc~f

`kzvx`t`fu ciul eciifd dlzcmtu cddfd woluf gxlvmd utctf fmfxgp u eilufx tl

tof elmdvet`lm hcmd1 u`mef tof fifetxlmu dl mlt oc~f cu ncx tl bvkz ilwfx

fmfxgp zoltlmu /toct `u ilmgfx wc~fifmgtou cmd ilwfx nxfsvfme`fu) cxf

uvnn`e`fmt tl tx`ggfx tof df~`ef- @n c uckzif ln u`i`elm ocu ulkf ln `tu ctlku

xfzicefd hp zoluzolxvu ctlku /`kzvx`t`fu) tofxf w`ii hf ftxc fifetxlmu

c~c`ichif nlx elmdvet`lm- To`u u cm fckzif ln cm ftx`mu`e ufk`elmdvetlx-

Zoltlxfu`utlxu cxf hcu`eciip zoltlefiiu-

http://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Conduction_bandhttp://en.wikipedia.org/wiki/Electron_holehttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Charge_carrierhttp://en.wikipedia.org/wiki/Valence_bandhttp://en.wikipedia.org/wiki/Bandgaphttp://en.wikipedia.org/wiki/Dopantshttp://en.wikipedia.org/wiki/Dopantshttp://en.wikipedia.org/wiki/Bandgaphttp://en.wikipedia.org/wiki/Valence_bandhttp://en.wikipedia.org/wiki/Charge_carrierhttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electron_holehttp://en.wikipedia.org/wiki/Conduction_bandhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Semiconductor

7/30/2019 Photoconductivity

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Uzfetxci xfuzlmuf ln EdU efii

Uzfe`n`ect`lm cmd kldfi

Tofxf cxf kcmp tpzfu ln zoltlxfu`utlxu w`to d`nnfxfmt uzfe`n`ect`lmu cmd

kldfiu- Zoltlxfu`utlxu ecm hf elctfd w`to lx zceacgfd m d`nnfxfmt kctfx`ciu

toct ~cxp tof xfu`utcmef dfzfmd`mg lm tof vuf nlx fceo IDX-

Czzi`ect`lmu

Zoltlxfu`utlxu elkf `m kcmp d`nnfxfmt tpzfu- @mfzfmu`~f ecdk`vk uvizo`df

efiiu ecm hf nlvmd `m kcmp elmuvkfx `tfku uveo cu eckfxc i`got kftfxu utxffti`gotu eilea xcd`lu cicxk df~`efu lvtdllx eileau ulicx utxfft ickzu cmd ulicx

xlcd utvdu fte-

Tofp cxf ciul vufd `m ulkf dpmck`e elkzxfuulxu tlgftofx w`to c ukcii

`mecmdfuefmt ickz lx i`got fk`tt`mg d`ldf tl elmtxli gc`m xfdvet`lm cmd cxf

ciul vufd `m hfd ickzu fte-

Ifcd uvin`df /ZhU) cmd `md`vk cmt`klm`df /@mUh) IDXu /i`got dfzfmdfmt

xfu`utlx) cxf vufd nlx tof k`d mnxcxfd uzfetxci xfg`lm- Gf2Ev zoltlelmdvetlxucxf cklmg tof hfut ncx+`mnxcxfd dftfetlxu c~c`ichif cmd cxf vufd nlx `mnxcxfd

cutxlmlkp cmd mnxcxfd uzfetxluelzp-

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