Diode phát quang và giải Nobel Vật lí 2014

	
8%!
		

W-\]!(G

!)
I,?!N
8"[B%?!&

8-.
=K
#
A(0!,?
!	!!*	
W"Z
;;!
A
A-H	A%&'
[
^D
%V"W

/

A
*!!	!_)	&_`
!!	!8?!:!
W
	)!-UF&;! 
W	!*8=a5Ob5c
[ (0;C

  
? !J
 !< 

% & &F   	 
W 8' A 
  
 C

(0 :
d8(G / &' !	!")_"F 
(G% &;! ,?!	!


8;(
*
*
=;8C(0	=I%8
0:!

'!e-
P 
(7 H" U#
 : C8 
A & 
 !	!  	
 8 !J
 
 
8
;?fg-h=

=%\-h8
&S-H
=
8
-

	

	
i	!	/
 !J
			

"Z;"7!d!*	
>
+8
?
!?"	$
+\-j-k
Vl
!!
!&C8235mn2o-p

*
 #8
;	

 
*><!
 8


I!
"8S.-q
;	
DL
	

DA		8&%(7;	!
d
F
!)N8			

d-r;	

!M(0! !1"7
s-&235bt23ua%8
&#
:?!?7 vL%&
# 23a5&
23b5LV!L"Q8
&""	
 !	!
!:Q!
*&N;	



+!
"8nao-H	

IA>A

('!=!):
A*
;
!J
!D
<!;
,!J
!	!&#
;"	$-

-HA :	
>		
8
'
*><!O-@8
'
*><!O(0!
e!!
#%!	!!
!A
+:

:
%!9!	!w
w!A
('(0!
-.	!!

	=*
0&'w
Q&		(0!	

	
>
	
-rI!

;%N

^!D
"	$!)=C(0
!
*-.	!
!)=
C(0	
*!/!d!*=_8%

8!*;D
-\;D
(0

, !J
 8
 
  
E Q !J
 Q 
 	
 
 &' Q !
  
 ' 
* ><! 
 8

=
G
V!-
U;! 
F8I!d7&#
 : !J
!	! !D
"	$& ' 
*><!Ox
&

#   23u5% (
 * 	
 8 


 
 y9 
: ;8 i
@ 7 lK & C8 23um P H" 2346 ! S!=A% i
 &
i


-.	
7 z8
'
*><!O!)
I8
?!?D
$I	

		-UC82342%Y-&!&!	!!
!y9

:;8S
.7lK nboV,?{ 
(7AI 
:!

;
(0;	

7S."d8!	!
8
;
'
*><!%

 )   
	 =*
 0 	
 > !J
 !	! !
 & w 
Q- @A  % C
(0
8(G


	
Bd=C(0!J
S.%&^N
>D
Z
	=*
0	
>!)=C>A
!	!
!D
]!!	!
=*8=A*
8

I-UC82344%!d!*;	

"d8(0!
!1878
Q0!D
gggOUnu%4o-UC82344&2346%j-k-\
A

y9 
:;8i@!18(0!Z; 
(0;	



	

DA78
8&!
	=*
0!J
!	!!

&w
Q
'
*><!On6ov8\F2-


.	! =K 
#
 !* 
 !	! ' 
* ><! O ;  &' P
h (0! 	
 
I

!)
C8
)-P
hD$"7=C(0
!

*!J
)%!|
	=*
0!
&w
Q8=L!/G*!	!
-YC(02%uU
(d1&'		-U8X
_
C8236a%&;!
	

DA	
>		
+'
*><!O(0!"	
!
nmo-U
	
)%	
>
7P
h7;

BmmY%
(0! !1 8 ! # & / (  
G "7 "
 )8   !1 

VP
!
!%gil%&y9
:;8lg@!%7lKnRO25o-@A
 %8D
&C8

F!	!
8'(0!,?V-HG
 	
 
I !J
 !	! T 
I P H" C8 a555 ! }- g- h~& & \-
Y8% & !	! * (0 
, 
 A% ! | 
8 !/8 
Q
 d !	! 

8
;
G88
[
D
%!	!
!)
I
 
?!
7;
9%&'!	!1?
NK&!
-


S

:;8"[/&!Q
# 2345n22o%
*"
&;!
!*

;,?P
y=C(0	
*"Za%aUx

"7"
)8 !1
y9
:;8@
e8y7
r1!\-P-P88%y9
:;8S&!!
!Sk7hj-
- h & !	! 9 
: ;8 !J
 V ; 
 i 7 lK l-
P€n2aO2uo-\^!)!	!8?!
 =	!
%
+
AN
L%
W	
&
ANF!*!	!_!E
TX
;
,&;
-S,?
!	!!D
?
=	!
&:?}Os]!H&'8(0
%
"('!)=	!
V(0!


+B
'?!-U!Q
# 2365%8

Q   >D
 7 !	! ('! =	! 
 V ! >D
 >(7 
 B & ?! 



 P
y-

.	!

I

"
8P
%h&yP
y>h2 t >D$'=K
#
&F
"('!)	

!)
IWd"('!)!P
h%

'&X==*
 
G = C (0  
! 
* &' > (' 5%u4- H- \A
= j- & !	!
!  
 y9 
: ;8 P
 !
! 7 lK% "W
 /   !1 &'
P
y>h2 t >&!Q
# 2345%&V
!L
&;!!*
!	!'

*><!O&
	

DA	
>
-S	
>
7"('!)
m2588B(0!"	!	&C8236an24o-
	
	 
!"
.(G(
*	
>		
8
B
=)=CdN-H
w !"
/&'}S&S.%&'=C (0	 
* '%=L(

*	
>		;-U#
;!|	

I!	!

8
P
HP
8H
-
#!!	"$%&'
P
H8
!D
"	$
!^gggOU%&'!D
<!

I
€
-H)!)
I
(0!L!DA
 !D
N
hasb]!S.%"D
!D=	!";
&N!	!
ZQ8-P
H!)
I(0!

%&:?&'!I
]!&'
8
8I
-rN=L
A&;!

8(7*	

FL!DA P
H
7 9-H)!%!	!=*8=A*



I
P
H(
*$!

Q
%
1!&#
;
 
!-P
H!)=
C (0 
! 
* b%u U% 
(d 1 &' 8
 "('! ) Z8 
 &X 
,
-
H
A
+!Q
# 2345%=C8
!L;
W	8',?
P
H% 8 =C (0 (G 

 V  (0!% (0! >8 >|
 8 
<! 
 !	!
9 !1!J
Vy-\-P-P88&\-Y8
V
(0!

	

;
+P
H
 8
&X[,?!	!!D


)
=	!
&"Z	!*V(0!!Dn26o-@A %<!DA&;!L!DA

 
IP
H&$!9D
=)-.E 
 
IB% 
 
"
%8' !) 
I
(0!

%
)!	!'
*><!O=L
I
(0!-UF
*%!	! 
!1
VyA*
T
#
&!D
P
y>8/
 -
.	! 
 
IP
H(0! 

;d&!Q 
# 2365"Z!	!
L!DAP
H
 8
!D
N,?=K
#
\Uy\AU
y



>Atl^!|y
\d\An2mo-l
Q9
:;87('!lK
n2R%23o%7H#
ina5o&7!ena2oV !1!	!=K
#
L!DA&

 
 P
H &' 8?! 
  	
 
I 
 
8% ( !	! 
7  &N &#
 ;
(G(&$=)=W!?!(0!-rN"N8]
&$=LN=I
(0!%&#
;L!D\Uy"Tx8"$!	!
!D
=8!AI
*&
&;!

"T
?)
!)8]
!J
A%

!	!1!!D

&'!D
#
!!
-U

9!J
A=L(0!Iz&<!DA-j-g-
y
=&% 8
  =
 
		C823mbnaaof‚

	





 

 



ƒI8

!1"TF
;=L!)F

()*$	+$	,-
U 
#   23m5% !	! =


>Atl^!|.X8ye


>Atl^!|y
\d\
!!
*!	!=K
#
A
!1P
H
A
+/C823mu%<!
l


 7 @=A- HC8 23R2% L (
H
A
&
*
?! !
!	! !  =	!- lV


:
Q
8'(0!!
!J
8
!w
:

IhH//
 =*

)(0!8) 
8)A%'!D
	


(
 
 )P
H!)

!DA<!/!
%(
8
 "N 8]
 !D
 (0 !
% )  !	 
8B
 ' 

/ 
  (G 

 
 (

^!  / 
 K &! A% V &
 !!
"
#$%

&

	'(
)*+&,
%
-


(.-
#/%
#$ 01
2$3%
-



;-l
/
*"-
."/
K 
#
 L !DA 
 
I 8'% il l!
 i
8
,nabo&lsUyl


!U
y

!dOY8nauo(0!	


IL!DAP
Hna4o-g
8h=

="
DAL
8&;!
U
0!  	 ( 
 
(
1!J
L&NP
H%!&'\h8
!X
* C8 23R6 
F P
H &' !D
 (0 
 

*
"Z=K
#
lsUyna6o-r
	
;8&
	
-l
'8Bb58



e
 !D
N
7;

;
L!DA!J
P
H2555.-@	
F
I8
=*
!D=*

B&'8
I8^! -l#
=*8=A*
!J



8

=8^!
 8&µ8-.)

D
 
 
^ I L !
"('!
)!J
	
 
I
-iZ
0! P
H !D
 (0 !
 !D ? !?
*
 8
 " "	
456%

'5617
8
	9

w! 

I-H(G

w
W
/ 
; !1
G r ^!
I !
 &
DA=*


D455.&

T('
IP
HL
I
(0!
DA !	! !D 
<!
!	!A% /
 >8 \F a
-

H(G 

 !M !) 
I 
 
 P
H &' 
 
  N 
D d 	 =I- S„
H
=
8

@#\)
!D
H!
%8
!L
)
!D
B7H#
i%

)V	

I8
(d	
(d

)hH(0!

A"Z
8
'8BP
HL!DA7;

DnaRo-
0$1#
l

7!:!&;!>D
'
*><!O=)=C
&;!


P
H"Z!	!N=I(0!-U!Q
# 23R5%h8
%h=

=
&!	!!V
*8

	


^…^I{Z= 
!1P
H

}&'=:I&;
,|
%)	

N		d
na3o%
+)!"*
&;!


Q
d-iZ8
!	!
(d
%=!*>
P
H

l&'!	!!
C(0
D%=*
!	!
:!D




Q
dnb5o-reA8

	

^&)V87(G
*
'!	!
'><!O7P
H-

@	!?!J
&;!!*>!
(0!
:!&C8
)%
8
"
"	!J
H
=
8
&!	!!nb2o-.	!
!!
(l]!}
1!
!D
 &' A &  ) 
7   
? - .	! !X8 !
 8 e 
1!!D
A&8=:!
!	!
!!
-H
=
8
!18Z
X8
>,:;
dA;!M$
'=:!
;!J
!	!

!!
l-@	!?!J
AQ&'&;!8
9
!	!!D
?


V(0!"*

+ !1
('!),?!	!&#
;=	!%"7y
=&nbao%
P-†-H8
=k
!nbbo%&(G=	!-
l
"('!
*
A*
&;!	

I

8;?L!DA&


!	!0=8hP
H%gP
H%)!	 
*
A*I>D
!	! '
*
><!T
I-.	!
*><!T
I(
*(0!;
!)
&/
# 2335
7)8 !1!J
h=

=$)8!J
H
=
8
nbu%b4o-
(-	$%2&$3415!67$
S	

I!J

&
!1
BZ!	!'
*><!
T
I&*(0
,!/
*
I
(0!;D
!
-@!	!!D
<!
(
*%!	!w
Q&!
(0!"d8&8

I
:!B
)
	
=*
0>A
;d&&' 
[
:
D
-h=

=&!	!!V
	

I!	!!D
<!

 hP
H‡P
Hnb6%bmo!9H
=
8

!L
'&'&;!=

	!!	!=*
0gP
H‡P
H&gP
H‡hP
HI

!	!'

* ><! T 
I% * (0 
,% & * (0 
, " nbRo- U C8 233u%
H
=
8
&!	!!V
(0!;D
(0
,a%mc,?8
'

*><!T
I=|gP
H‡hP
H>8\Fbnb3o-U'"('!	

I
/ 
 
 
^A%  
FV z/('*	
 
I
 
8&
1 ? !J
 !< 87 
 
('! 8W
- . 
  N 
* 
?! 	
 
I 


8%('
';D
!
d%
:
&!	!1?-S	
>


8

 P
H(0!
	

DA&C82334t2336"7!
)8nu5%
u2o-
.	!
Q!P
H;A
A=*
!J
8
!w!	!
	

 K &! &#
 : &#
 ; !d " & L !DA 
 
I% 
 K &! &#
 :
?!?&'
*
=*!D
<!T
I
 
*%&
K&!
:^!&'

Q()
=*
0	

-@*
FT!,!J


8%?!%B&

‚
Wƒ(0!
)8
W

F7


-
8&9
.L;
W	;


8
!!!	!8%) !AI

*
+")_
&_Q`

!L;
-i)_

9%(0!	
8"7@8
&C82Rm3%!);D

D!ˆ26
8‡%
(d(d&';D
C(0=uc;C(0!"*
[ 
	 	-8 8 d&T XI8L 

 
L%)>|

*  1 [ !J
 8W
 (G- r_ Q ` 
% !1
 
JA e &
(0!	
8"7y-.\‰

&C82355%

';D
m58‡-
	
.	!

W;
A

'db55 8‡%
(d(d&';D
!W8

(G
 45c-

:-@*
FT!,!J


(d8-@:!
+nuao-y.O
&*

W
!J
		

W"*[%
\!D
<!T
I=|-\;D
!W8
(G
EQ
!LD

			

&!LD
;!!D-
.	!

WX

W	
(G


 

8=:!

:!I		
8"*
		
W-.	!
!D
(0
!
A!X&'
[
^D
!J
!<255555G
A!Š%&

T
(G;
"X[-@
(d
/%!	!
"
8A!)
I


A 
* ! =*
 0 !J
 
 
8 &  I 
W 	 ; - .L
;A‹!|N=I
/8W!-
U;!

A
*")_
9&_Q`
"Z
‹(
*
!W
8	=I!/C(0X!
W	-UFa5Oa5c;C

 
?
K&!=
*!L;X!
W	%! (G



 D
N(	 !&;! 

A 
*!	! !L; 
W	!M
"Z!L;
-
HA
A%!	!
Q!P
H!!D!L;!)1!!

!
!!	!
8I
T

IB!*	(0!7N;
%8	A
:
"%

%8F&
:%8F
&%&e&e-.	!
P
H	

	
8&
,!9(0!X
!	!
U
8#
!
%8!	!8
!L;(
e8!%F&8-Œ?

(d
!)

I"
8&;!,?
hP
H‡P
H	
>
,I^!('!%&F	
	
,	Bh
H!J
&=%&&&&#
-q>17
!(
!);]!8('!D;
=L;%;C


+!	!
D88]

G(


!A&"
A‹
W	!	!




W&"
 8-q)%!<

!1=*8
	
!
*
+_
/


W-

;5!<	$"=
2-\-j-k%:
3%);%
%b5R235m-
a-s-U-&%=3
3%>?=3
3>
?#3@A%	<	::%uR423am…A
)B)?@25au
23aR…*)C3
%b6b23u5…FEEC3
2a23223a3-
b-Y-&!%.-h-h!!
Ž-j
8!
%A?1)C3	)BA%65b2342-
u-P-h-~~%k-h-\"
Žj-
-i%A?1)C3	)CC%22uu2344-
4-k-i

%A?1)C3	)>>%2R3a2344-
6-j-k-\
A%A?1)C3	)>B%2R662344…j-k-\
AŽ-.-

%A?1)C3	)
C%26m62346-
m-j-g-y
=&%A?1)C3	)G3)>%aRbOaR4236a…j-g-y
=&Žj--i=A%
A%)HC:%DC%23m6O23mm236a…k-j-YAŽ@-l-
%A%)HC:%DC%2RaaO2Rab
236a-
R-k-H-\
%P--†%j-
-YA%@-j-S
AŽk-s-.
%A?1)C3	)G3)
>@b66tb6R236a-
3-l-g-H

%-y-
8=%P-i%†-\-
ŽP-
%D
)A?1)G3)@
6at6b236a-
25-@-l-
%k-\-k=3
)D
)A?1)G3)@32236a-
22-P-h-~~%k-h-\"
Žj-
-i%A?1)C3	)CC%22uu2344…
-h-\
%
P-†-h~AŽ.-S-%6%3B%253234R-


2a-\-P-P88Ž\-Y8
%A?1)C3	)EA%23b32362…\-P-P88
Ž\-S!€%A?1)G3)B%abb236u-
2b-j-S

=‰!€Žj--h%I)A?1)*3)E
<1EA%RR2236a-
2u-l-P€Žk-l-l=A
=%I)D
)A?1)AE%2bbR2362-
24-H-\A
=ŽS-†-i&
!
%D
)A?1)G3)@Ra236a-
26- \-P- P88 
 \- Y8
% J) >) 6%>%1) :% a6u 2343… D% m33
2365…\-P-P88%\-Y8
Žg-i-l

=%53%
3
%
iy25mmbb5
2365-
2m-\-y-l
=
Žj-j-@
„%D
)A?1)G3)D%bam2363-
2R-k-
%
-
-S%S--S
=‰=Žl-g8%A?1)C3	) :%2a2223m2-
23-j-gy
=&%-h-l%
-k!8
Žj--i=A%I)G
):%6b%23m2…
B%R323mb…\-y-l
=
%
-h-S
&
j-g-y
=&%D
)A?1)G3)EE%
b5b23mb-
a5- l- S
 Ž l- h=% I
) I) D
) A?1) D% 23ub 23m6-
a2-\-P-P88Ži-l8
% I)D
)A?1):%u54u 23m5…i-l8
%
A?1)C3	) C@6m623mu-
aa-j-gy
=&%I)G
)F%22u23mb-
ab-h--.Žj-k-h
%A%)E
<E3*3)C%24m23m4-
au-\-l-l

&
%†-l-8
Ž-g-S8%I):
3%3)E)B%2R6u
23m2-
a4-S-
%S-l
‰
ŽS-P
%D
)A?1)G3):B%b4b2346-
a6-\-h8
%H-S
‰
=%g-h=

=Ž-@A
%D
)A?1)G3):B%b4b23R6-
am-Y-\
8
3
)%I)*%?1
5%KD%6aR2332-
aR-S-H
=
8
%I
)I)D
)A?1-AC%2m542332…S-H
=
8
%l-S%Ž@-
l=
%I
)I)D
)A?1)AC%233R2332-
a3- \- h8
% g- h=

=% @- Y€
‰
% Y- \
8
% H- S
‰
=% Y- g=
 Ž -
g%I)G
):CG:%2a223RR-
b5-\-h8
%l-Y
%Y-\
8
%Žg-h=

=%I
)I)D
)A?1)EB%a22a
23R3-



b2- S- H
=
8
% H- g‰

% l- S% Ž @- l=
% I
) I) D
) A?1) A% 2a4R
233a…S-H
=
8
%@-l=
%l-SŽH-g‰

%I
)I)D
)A?1)A%2b3
233a-
ba-j-g-y
=&%
--.
%j--i=AŽk-s-
!%A?1)C3	)G3)D%
aaau23Rb-
bb-P-†-H8
=k
!%FE3
4a4au3323RR-
bu-\-l
=
8%@-h
%\-h8
%Y-\
8
%H-S
‰
=Ž