PhotodiodeSCIENCEANDTECHNOLOGY

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CutovnguynlhotngXthaitmbndn,mtthucloiNvmtthucloiP,ghptipxcnhau.

TimttipxchnhthnhmtvngnghohtdnvtivngnytntimtintrngvhnhthnhhngrothV .

Khikhngcinthngoit lnchuyntip(V=0),dmginchyquachuyntipi=0,thctdngIchnhldngtngcngcahaidnginbngnhauvngcchiu:

Dngkhuchtncchtcbnsinhrakhiionhocctpcht(ltrongtrongbndnloiP,inttrongbndnloiN)donnglngnhitcacchtdncbnlnvtquahngroth.

Dnght dn khngcbn sinh rado kch thchnhit (in t trongbndnP, l trng trongbndnN)chuynngditcdngcaintrngEtrongvngngho.

Hnh8.1:SchuyntipPNvhiungquangintrongvngngho

Khicinptlnit,hngroththayikotheosthayidnghtcbnvbrngvngngho.Dnginquachuyntip:

Khiinpngcln:

,

chiucaohngrothlnnmcdngkhuchtncacchtcbntrnnrtnhvcthbquavchcnlidngngccait,khii=I .

Khichiusngitbngbcxcbcsngnhhnbcsngngng,sxuthinthmcccpintltrng.cchtdnnythamgiadnincnphingncnstihpcachng,tclnhanhchngtchri cpin t l trng.S tch cpin t l trng ch xy ra trong vngnghonh tcdng cain

TILIU

1Thch 1Chias

b

0

trng.

Shtdncgiiphngphthucvothnglngnhsngttivngnghovkhnnghpthcavngny.Thnglngnhsngchiutivngnghophthucngkvochiudy lpvt liumniqua:

Tronghs10 cm .tngthnglngnhsngnvngnghongitachtoitviphinbndnchiudyrtb.

Khnnghp thbcxph thuc rt lnvob rngvngngho. tngkhnngmrngvngnghongitadngitPIN, lpbndnringIkpgiahai lpbndnPvN,vi loiitnychcninpngcvivncthmrngvngnghoratonblpbndnI.

Hnh8.2:CutoitloiPIN

ChhotngChquangdn:

Snguynl(hnh8.3a)gmmtngunEsphnccngcitvmtintrRmotnhiu.

Hnh8.3:Snguynlvchlmvic

Dngngcquait:

(8.1)

TrongI ldngquangin:

(8.2)

KhiinpngcV ln,thnhphn

5 1

P

d

tac:

Thngthng

Phngtrnhmchin:

TrongV =R I chophpvngthngti(hnh8.3b).

Dnginchytrongmch:

imlmviccaitlimgiaonhaugiangthngtivngctuynIVvithnglngtngng.Chlmvicnyltuyntnh,V tlvithnglng.

Chquangth:

Trongchnykhngcinpngoitvoit.itlmvicnhmtbchuyninnglngtngngvimtmyphtvngitaothhmchV0ChocodngngnmchISC.

othhmch:Khichiusng,dngIPtng lmchohngrothgimmt lng?Vb.Sgimchiucaohngrothlmchodnghtdncbntngln,khitcnbngIr=0.

gimchiucaoV cahngrothcthxcnhcthngquaoinpgiahaiuitkhihmch.

KhichiusngyuI I vtac:

TrongtrnghpnyV cgitrtngiln(c0,10,6V)nhngphthucvothnglngtheohmlogarit.

R m r

R

b

P 0

OC

p 0

OC

Hnh8.4:Sphthuccathhmchvothnglng

odngngnmch:Khiningnmchhaiuitbngmtin trnhhn rno,dngonmch IchnhbngIvtlvithnglng(hnh8.5):

Hnh8.5:Sphthuccadngngn

mchvothnglngnhsng

cimquantrngcachnylkhngcdngti,nhvycthgimnhiuvchophpocthnglngnh.

nhyivibcxcphxcnh,dngquanginIPtltuyntnhvithnglngtrongmtkhongtngirng,c56decad.nhyphxcnhtheocngthc:

Vi= .

nhyphphthucvo,hiusutlngt,hsphnxRvhshpth.s

Hnh8.6:Phnhycaphotodiode

NgisdngcnphibitnhyphdatrnngcongphhipS()/S( )vgitrcabcsng ngvinhycci.ThngthngS( )nmtrongkhong0,11,0A/W.

Hnh8.9:Sphthuccanhyvonhit

Khinhit tng,cci cangcongphdchchuynvphabcsngdi.Hsnhitcadngquangdn

cgitrkhong0,1%/ C.

SngdngphotodiodeSlmvicchquangdn:

ctrngcachquangdn:

+tuyntnhcao.

+Thigianhipngn.

+Dithngln.

Hnh8.9trnhbysodngngctrongchquangdn.

Scs(hnh8.10a):

P

P P

P

o

Hnh8.10:Smchodngngctrongchquangdn

KhitngintrR slmgimnhiu.Tngtrvocamchkhuchiphilntrnhlmgimintrtihiudngcait.

Stcngnhanh(hnh8.10b):

intrcaiotnhvbng

trongKlhskhuchitnslmvic.TC ctcdngbtrnhhngcatksinhC viiukin

.Bkhuchiyphicdngvortnhvssuygimdonhitcngphikhngngk.

Slmvicchquangth:

ctrngcachquangth:

+Cthlmvicchtuyntnhhoclogarittuthucvoti.

+tnhiu.

+Thigianhipln.

+Dithngnh.

+Nhycmvinhitchlogarit.

Stuyntnh(hnh8.11a):odngngnmchI .

Trongchny:

Slogarit(hnh8.11b):oinphmchV .

m

2 pl

sc

oc