Photodetector (Finalized)

8/16/2019 Photodetector (Finalized)

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PHOTODETECTORGROUP 5Nooraisyah Binti Abdullah(175 !!"

A#lina Binti Ta$uddin (175!5!"Ann% Tha& (17' ! "



)hat is a Photod%t%*tor+•

Con,%rts o-ti*al si.nal (li.ht" into%l%*tri*al si.nal

/ 0olta.% / Curr%nt

•

R%s-ons% is -ro-ortional to th%-o %r in th% b%a&

• 2n*lud% any d%,i*% 3or r%.ist%rin.-hotons ith 3r%4u%n*i%s abo,%

that o3 radio a,%s 3ro& 3arin3rar%d on u- to .a&&a rays• )id%ly us%d in o-ti*al

*o&&uni*ation syst%&s



• Th% 3unda&%ntal %l%&%nt o3 o-ti*alr%*%i,%r6 3ollo %d by a&-li %rs andsi.nal *onditionin. *ir*uitry

• 2t or8s on th% -rin*i-l% o3Photo%l%*tri* %9%*t



• )h%n a -hoton o3 su:*i%nt %n%r.y %nt%rs th%d%-l%tion r%.ion o3 a s%&i*ondu*tor diod%6 it &aystri8% an ato& ith su:*i%nt %n%r.y to r%l%as%

th% %l%*tron 3ro& th% ato&i* stru*tur%;• This *r%at%s a 3r%% %l%*tron and a hol% (i;%; an

ato& ith a s-a*% 3or an %l%*tron";• Th% %l%*tron is n%.ati,%ly *har.%d6 hil% th% hol%

is -ositi,%ly *har.%d;• Th% %l%*trons and hol%s &ay r%&ain 3r%%6 or oth%r%l%*trons &ay *o&bin% ith hol%s to 3or&*o&-l%t% ato&s a.ain in th% *rystal latti*%;

• Ho %,%r it is -ossibl% that th% %l%*trons and hol%s&ay r%&ain 3r%% and b% -ull%d a ay 3ro& th%d%-l%tion r%.ion by an %<t%rnal %ld;

• 2n this ay th% *urr%nt throu.h th% diod% ill*han.% and a -hoto*urr%nt is -rodu*%d;



• 23 %l%*tri* %ld i&-os%d on -hotod%t%*tor6 an%l%*tri* *urr%nt (-hoto*urr%nt" is -rodu*%d

• -hotodiod%



History• =ohn N; >hi,% as an A&%ri*an -hysi*ist and

in,%ntor ho &ad% r%&ar8abl% *ontributions insolid stat% -hysi*s and %l%*troni* %n.in%%rin.durin. th% %arly days o3 d%,%lo-&%nt o3transistors at th% B%ll T%l%-hon% ?aboratori%s;

• Graduation in -hysi*s and *h%&istry in th% y%ar1@ ! and PhD in th% y%ar 1@ @;

• 2n 1@! 6 th% >hi,% i&-li*at%d li.ht b%a& inst%ado3 %&itt%r t%r&inal as ir% 3or transistor6.%n%ratin. hol%s that o ,ia *oll%*tor latt%rly

this d%,i*% as a--%llat% as -hototransistor;



RE U2RE ENT>• Good s%nsiti,ity (r%s-onsi,ity" at th%

d%sir%d a,%l%n.th and -oorr%s-onsi,ity %ls% h%r% a,%l%n.th

s%l%*ti,ity• Fast r%s-ons% ti&% hi.h band idth• Co&-atibl% -hysi*al di&%nsions•

?o nois%• 2ns%nsiti,% to t%&-%ratur% ,ariations• ?on. o-%ratin. li3% and r%asonabl%

*ost



od%s o3 o-%ration

PHOTO0O?TA2C ODE• %ro bias th%r&al %4uilibriu& stat%• o-%rat%d ith no a--li%d ,olta.%;• -ro,id%s lo nois%

PHOTOCONDUCT20E ODE• R%,%rs% bias / th% only *urr%nt that *an o is th%

r%,%rs% *urr%nt6 du% to th%r&ally .%n%rat%d

&inority *arri%rs• a*ti,at%d h%n th%r% is an a--li%d r%,%rs%,olta.%

• r%sults in a hi.h%r r%s-ons% s-%%d than-hoto,oltai*

• in*r%as%d nois%



ain Ty-%s o3Photod%t%*tor

• &ain ty-%s1; Photodiod%

;P2N -hotodiod%;A,alan*h% -hotodiod%

!; Phototransistor



Photodiod%• Photo &%ans li.ht• Diod% &%ans a d%,i*% -%rtainin. o3 t o

%l%*trod%s• A -hotodiod% is a li.ht s%nsiti,% %l%*troni*

d%,i*% *a-abl% o3 *on,%rtin. li.ht into a,olta.% or *urr%nt si.nal;

• bas%d on a $un*tion o3 o--osit%ly do-%dr%.ions (-n $un*tion"

• diod% is o-%rat%d und%r r%,%rs% bias*onditions;



P2N Photodiod%• R%,%rs%d bias hi.h r%sisti,ity o3 th% intrinsi*

lay%• ?ar.%r d%-l%tion r%.ion lo %r *a-a*itan*%• Th% illu&ination indo 3or a P2N is on th% P/sid%

o3 th% diod% b%*aus% th% &obility o3 %l%*trons is.r%at%r than hol%s hi*h r%sults in b%tt%r3r%4u%n*y r%s-ons%



Pin Photodiod%

The high electric field present in the depletion region causes photo-generated carriers to separate and be collected across the reverse –

biased junction. This give rise to a current flow in an external circuit,known as photocurrent ;



A,alan*h% -hotodiod%s(APD"

• Hi.h s%nsiti,ity6 hi.h s-%%d s%&i*ondu*torIli.htJ s%nsors;

• Co&-ar%d to r%.ular P2N *onstru*tion-hotodiod%s6 APDs6 ha,% an int%rnal r%.ion

h%r% %l%*tron &ulti-li*ation o**urs bya--li*ation o3 an %<t%rnal r%,%rs% ,olta.% andth% r%sultant I.ainJ in th% out-ut si.nal &%ansthat lo li.ht l%,%ls *an b% &%asur%d at hi.h

s-%%d;• 2n*id%nt -hotons *r%at% %l%*tron hol% -airs inth% d%-l%tion lay%r o3 a sili*on -hotodiod%stru*tur% and th%s% &o,%s to ards r%s-%*ti,%%l%*trod% a**ordin. to %l%*tri* %ld str%n.th;



•

O-%rat%d ith &u*h hi.h%r r%,%rs%bias;• This allo s %a*h -hoto/.%n%rat%d

*arri%r to b% &ulti-li%d by a,alan*h%br%a8do n;

• Th% %9%*t is 8no n as i&-a*tioni#ation a,alan*h% %9%*t;

•

R%sultin. in int%rnal .ain ithin



Phototransistor• Phototransistor is d%si.n%d to a&-li3y th% out-ut

3ro& a -hotodiod% usin. a transistor;• Pro,id%s hi.h%r out-ut si.nal l%,%ls;• >tru*tur% that basi*ally *o&bin%s a -hotodiod%

and a transistor;



• COMMUNICATIONS- E<a&-l%K Fib%r o-ti*

*o&&uni*ations

• REMOTE-SENSING-

E<a&-l%K >a3%ty L

A--li*ation



Fib%r o-ti* *o&&uni*ationssyst%&s

• Photod%t%*torso-%rat% at 2Rr%.ion

•

D%t%*tors ar%-hotodiod%s(2nGaAs"

• Data*o&&uni*ationrat%s as hi.h as

;5 Gbits s



>a3%ty and >%*urity• Th% d%t%*tion o3 th%

-r%s%n*% or abs%n*% o3 anob$%*t;

•

D%t%*tors ar%-hoto*ondu*tors;• Collision d%t%*tion in

auto&obil% industry;• 2n 3a*tori%s6 th% %l%*tri*al

ar* d%t%*tion auto&ati*ally*uttin. o9 th% *urr%nt

h%r% ar*in. o**urs;



En,iron&%ntal >%nsin.• Pollution d%t%*tion by U0

s-%*tros*o-y• Fluor%s*%n*% s-%*tros*o-y• Ch%&ilu&in% s*%n*%• >olid -arti*ulat%s in air and at%r

*an b% d%t%*t%d by a&ount o3li.ht s*att%r%d

• ?idar s*att%rin. 3or &onitorin. o3-ollution o,%r lar.% ar%as

• >at%llit%/&ount%d 2R



>U ARM• A -hotod%t%*tor is an o-to%l%*troni* d%,i*%• Absorbs o-ti*al si.nals and *on,%rts th%& into

%l%*tri*al si.nals;• Th% $un*tion us%s an illu&ination indo ith an

anti/r% %*t *oatin. to absorb th% li.ht -hotons;• Th% r%sult o3 th% absor-tion o3 -hotons is th%

*r%ation o3 %l%*tron/hol% -airs in th% d%-l%tionr%.ion su*h as -hotodiod%s and -hototransistors;

•

Th% basi* r%4uir%&%nts o3 a -hotod%t%*tor ar%s%nsiti,ity at th% r%4uir%d a,%l%n.th6 %:*i%nt*on,%rsion o3 -hotons to %l%*trons 3ast r%s-ons%to o-%rat% at hi.h 3r%4u%n*i%s6 lo nois% 3orr%du*%s %rrors6 su:*i%nt ar%a 3or %:*i%nt

*ou-lin. to o-ti*al b%r6 hi.h r%liability and lo*osts;



THANK YOU

Photodetector (Finalized)

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