¶  ¥} º­ Ž U ê s0 n É; c 8 ýA 0 V R ËX ê sc Ü R HVPE-LED8 ý — ¤V R Ë

Ì g

¶  ¥} º­ Ž U ê s0 n É; c 8 ýA 0 V R ËX ê sc Ü R HVPE-LED8 ý — ¤V R Ë

T

 ‡ m r · b 9 g Y @¬ £ ·  ™ »ª <® £ · T ~ ç ¡) o  · ÷ 6 ; . > ª < · ‚ Ð ò 6 BT Ö h ·  ™ »# Ü é s · … è ¡ * > · T „ ‘ ž$ ß  · ¼ ÿ ›0 ï F¬ £

ô

 Dz D G K € ª œ@ /† < Ɠ §
” ¸ì ø ͕ ¸^ ‰„  / B N,  Òí ß – 606-791

‚ Ð=  ÷ 7 B

Â

Òí ß –@ /† < Ɠ §
” ¸B jn (  / B N † < Æõ ,  â · ¡ ¤ 760-749

™ ») o Z 9 

î

ß –1 l x @ /† < Ɠ § Ó ü t o † < Æõ , î ß –1 l x 760-749

 ý — ¡® £

CSsol ( Å Ò),  Òí ß – 606-791

(2010¸   3 Z 4 15{ 9  ~ à Î6 £ §, 2010¸   4 Z 4 28{ 9  à º& ñ ‘ : r ~ à Î6 £ §, 2010¸   5 Z 4 12{ 9  > F  S X ‰& ñ )

‘ :

r  7 Hë  H \ " f  H ™ D ¥ ½ + ˙ èÛ ¼ HVPE(hydride vapor phase epitaxy) ~ ½ ÓZ O `  ¦ s 6   x # Œ In € ª œ_     o\   



É r 4" é ¶ >  InAlGaN 8 £ x`  ¦  Ö ¸$ í 8 £ x Ü ¼– Ð   H LED(light emitting diode)\  ¦ ] j Œ • % i  . LED_  ½ ¨› ¸  H (0001) n-GaN   s # Q l ó ø Í 0 A\  n-AlGaN 9 þ t A ` ç 8 £ x,  Ö ¸$ í 8 £ x, p-AlGaN 9 þ t A ` ç 8 £ x, Õ ªo “ ¦ p-GaN Ö “ s 8

£

x í  H " f– Ð $ í  © œ % i “ ¦ ì ø Í6 £ x› ' a _  “ : r • ¸  H ™ èÛ ¼ % ò % i  900

C, $ í  © œ % ò % i  1090

C – Ð Ä »t  % i  . Alõ  Gas 

™ D

¥ ½ + ˝ ) a B j» 1 ϙ èÛ ¼\  In € ª œ`  ¦ 0.1 g \ " f 0.5 g t  › ¸] X  # Œ LED : £ ¤$ í _     o\  ¦ · ú ˜ ˜ Ѐ Œ ¤Ü ¼ 9 InAlGaN 8

£

x ? /_  Inõ  Al_     o\  ¦ · ú ˜ ˜ Ðl  0 AK  SEM(scanning electron microscope), XPS(X-ray photo- electron spectroscopy), EDS(energy dispersive X-ray spectroscopy), EL(electroluminescence)`  ¦ 8 £ ¤

&

ñ % i  . XPSü < EDS_    õ \  ¦ : Ÿ x K  Inõ  Al $ í ì  r`  ¦ S X ‰ “   “ ¦ In € ª œs  7 £ x † < Ê\     Al € ª œs  y Œ ™™ è

†

< Ê`  ¦ · ú ˜ à º e ” % 3  . EL spectrum   õ  420 nmü < 515 nm, 547 nm\ " f peak › ' a ¹ 1 Ï÷ &% 3 Ü ¼ 9 Ñ þ ˜Ò  o µ 1 Ï F 

g`  ¦ S X ‰ “   % i  . s  Qô  Ç   õ [ þ t`  ¦ : Ÿ x K  In € ª œ_     o HVPE-LED_  Ñ þ ˜Ò  o µ 1 Ï F  g`  ¦ ½ ¨‰ & ³   H X < l 

“

 † < Ê`  ¦ · ú ˜ à º e ” % 3  .

Ù þ

˜d ” # Q: InAlGaN, Ñ þ ˜Ò  o LED, HVPE, ™ D ¥ ½ + ˙ èÛ ¼ Z O 

Characterization of a HVPE-LED Grown by Using the Mixed-source Method

A. R. Lee · H. S. Jeon · E. J. Kim · G. S. Lee · J. E. Ok

· D. W. Jo · K. H. Kim · M. Yang · S. N. Yi · H. S. Ahn ^∗

Department of Applied Sciences, Korea Maritime University, Busan 606-791

C. R. Cho

Department of Nanomedical Engineering, Pusan National University, Gyeongnam 627-706

S. W. Kim

Department of Physics, Andong National University, Andong, Gyeongbuk 760-749

H. Ha

-511-

CSsol Co. Ltd., Pusan 606-791

(Received 15 March, 2010 : revised 28 April, 2010 : accepted 12 May, 2010)

In this study, we use quaternary InAlGaN layers with various indium compositions that were grown for white LED (light emitting diode) by using the mixed-source HVPE (hydride vapor phase epitaxy) process. The epitaxial structures of the HVPE-LEDs were grown on templated n-GaN (0001) sapphire. The structures of the HVPE-LEDs consisted of a Te-doped n-type GaN layer, an Al(In)GaN active layer, a Mg-doped p-type AlGaN (p-AlGaN:Mg) layer, and a Mg-doped GaN contact layer. The temperature of the source zone and that of the growth zone were 900

C and 1090

C, respectively. In order to investigate the changes in the LED characteristics, are varied the amounts of metallic In mixed with Al and Ga in the active source well from 0.1 g to 0.5 g. We investigated the InAlGaN layers to determine the effects of In and Al by means of SEM (scanning electron microscopy), XPS (X-ray photoelectron spectroscopy), EDS (energy dispersive X-ray spectroscopy), EL (electroluminescence). When the In quantity increased, the Al atomic percent decreased in the EDS result for the active layer surface. The EL measurement showed peaks located at 420 nm, 515 nm, and 547 nm. Consequently, we have demonstrated the possibility of fabricating white LEDs without phosphor by using the mixed-source HVPE method.

PACS numbers: 61,46,81.05Ea,81.15.Kk

Keywords: InAlGaN, White LED, HVPE, Mixed-source method.

I. " e  ] Ø

t

è ß – à º ¸  ç ß –,  Œ •“ É r ™ èq „  § 4 õ  |   à º" î `  ¦ ”   Ñ þ ˜Ò  o LED(light emitting diode)  H l ” > r _  + þ AF  g1 p x \ " f µ 1 ÏÒ q t 



 H à º“ É r õ  ° ú  “ É r š ¸% i Ó ü t| 9 `  ¦ K     9  € ª œô  Ç ì  r  \  6 £ x 6

x ) a    H  © œ& h  M :ë  H \  › ' a d ” s  7 £ x  “ ¦ e ”   [1,2].

Ñ þ

˜Ò  o LED  H ß ¼>  [ j t _  ~ ½ ÓZ O `  ¦ s 6   x # Œ % 3 `  ¦ à º e ”

 . ' Í   P : ~ ½ ÓZ O “ É r  ×  æ } 9 `  ¦  6   x   H l Õ ü t – Ð" f y n C _

  Œ ™" é ¶Ò  o“   RGB_  3> h } 9 `  ¦ › ¸½ + Ë # Œ ] j Œ •   H  כ s 



. Õ ª Q
, s  Qô  Ç ~ ½ Ód ” “ É r y Œ •y Œ •_  } 9    1 l x  Œ •„  · ú šs  Ô  ¦ ç

 H{ 9  “ ¦, Šҁ   “ : r • ¸\     y Œ •y Œ •_  } 9 _  Ø  ¦§ 4 s     # Œ Ò 

o ý a³ ð ² ú ˜ t  9  r– Ð 4 Ÿ ¤ ¸ ú šK ”     H é ß –& h s  e ”   [3]. ¿ º   P : ~ ½ ÓZ O “ É r ' õ AÒ  o   © œ@ /_  InGaN LED\  ” ¸ê ø Í Ò 

o + þ AF  g ^ ‰\  ¦   ½ + Ëô  Ç ~ ½ ÓZ O s   [4–9]. Õ ª Q
 ' õ AÒ  oõ  ” ¸ ê

ø ÍÒ  o_    © œ ç ß –  s  V , # Q" f Ò  oì  r o – Ð “  ô  Ç $ 3 F  g ´ òõ – Ð

“

 K  Ò  o ý a³ ð 1 l x{ 9 ô  Ç Ñ þ ˜Ò  o LED_  € ª œí ß –s  # Q§ > “ ¦ ¢ ¸ ô

 Ç › ¸" î F  g " é ¶ \ " f ×  æ כ ¹ô  Ç   à º“   CCT(correlated color temperature) _  › ¸] X • ¸ q “ §& h  # Q 9Ä º 9 & h Ò  o µ 1 Ï F  g s  €  •

l  M :ë  H \  CRI(color rendering index)t à º Ø  æì  r t 

· ú

§  [10, 11]. ¢ ¸ô  Ç + þ AF  g ^ ‰\  ¦  6   x Ù ¼– Ð • 2 ;¨ 8 Š â & h s t  3

l

w ô  Ç é ß –& h s  e ”  . [ j   P : ~ ½ ÓZ O “ É r y Œ •l    É r Ò  o`  ¦ ~ ½ ÓØ  ¦

  H € ª œ Ä ºÓ ü t _  & h 8 £ x`  ¦ s 6   x   H  כ “  X <, s  ~ ½ ÓZ O “ É r y n C

∗

E-mail: ahnhs@hhu.ac.kr

_

 y © œ• ¸\  ¦ › ¸] X  l  # Q§ >    H é ß –& h s  e ”  . ‘ : r  7 Hë  H \ " f



 H s  Qô  Ç ë  H ] j& h [ þ t`  ¦ K    l  0 AK ,  © œ  â ] j& h s  9

•

2 ;¨ 8 Š â & h “   ~ ½ ÓZ O _  
– Ð é ß –{ 9  } 9 \ " f + þ AF  g ^ ‰\  ¦  6   x

t  · ú §“ ¦ Ñ þ ˜Ò  oF  g`  ¦ ~ ½ ÓØ  ¦   H } 9 `  ¦ ƒ  ½ ¨ % i  . s \  ¦ 0 A K

 multi sliding boat r Û ¼% 7 ›`  ¦  6   x ô  Ç ™ D ¥ ½ + ˙ èÛ ¼ HVPE Z O

`  ¦ s 6   x % i Ü ¼ 9 4" é ¶ >   o½ + ËÓ ü t“   InAlGaN Ó ü t| 9 `  ¦  Ö ¸

$ í

8 £ x Ü ¼– Ð ½ ¨$ í % i  . Ä ºØ Ô s à Ô ½ ¨› ¸_  InAlGaN“ É r V , 

“

É r  ½ ™× ¼Ì “ s`  ¦ ° ú   H f ” ] X …  ;s + þ A Ó ü t| 9 – Ð" f : £ ¤ y  “ ¦$ í 0 p x`  ¦ 0

A # Œ > hµ 1 Ï ÷ &# Q M ® o  . InAlGaN _  \  -t   ½ ™× ¼Ì “ s“ É r › ¸

$ í

q \     1.95 eV\ " f 6.2 eV t  › ¸] X  ) a  . ¢ ¸ô  Ç  H

\

 -t   ½ ™× ¼Ì “ sõ  „  • ¸@ / offset M :ë  H \  UV % ò % i \  K { © œ

  H F  g ™ è  > hµ 1 Ïõ   € ª œô  Ç 6 £ x6   x`  ¦ 0 A # Œ Å Ò3 l q`  ¦ ~ à Î

“

¦ e ”   [12–21]. ¢ ¸ô  Ç, AlGaNõ  q “ § % i `  ¦ M : GaNõ 

 

  © œÃ º s  & h # Q „  0 A\  ¦ ×  ¦ # Œ Å Ò 9, y © œô  Ç  µ 1 Ï ~ ½ Ó Ø

 ¦ 1 p x _   © œ& h `  ¦ t     כ Ü ¼– Ð ˜ Г ¦÷ &“ ¦ e ”   [22].  ü @

‚

 s  y © œ >  ~ ½ ÓØ  ¦ ÷ &  H  כ “ É r InGaN $ í  © œ\ " f In_  K o 

\

 _  # Œ " l or — : r s  ² D G ™ è& h Ü ¼– Ð F   ½ + Ë   H  כ Ü ¼– Ð
 


 9, s   H  ½ ™× ¼ ç ß –_  …  ;s – РÒ'  µ 1 Ï F  g ÷ &  H  כ Ü ¼– Ð ˜ Ð

“

¦  ) a  . ‘ : r  7 Hë  H \ " f  H ™ D ¥ ½ + ˙ èÛ ¼ HVPE(hydride vapor phase epitaxy) ~ ½ ÓZ O Ü ¼– Ð In € ª œ_     o\    É r InAlGaN

 Ö

¸$ í 8 £ x`  ¦ ° ú   H DH(double hetero) ½ ¨› ¸\  ¦ $ í  © œ % i Ü ¼ 9, s

\     LED : £ ¤$ í x 9  $ í  © œ  ⠆ ¾ Ó$ í `  ¦ ì  r$ 3  l  0 A 

#

ΠEDS(energy dispersive X-ray spectroscopy), XPS(X-

ray photoelectron spectroscopy)`  ¦ 8 £ ¤& ñ % i “ ¦ ™ è – Ð" f

Fig. 1. Schematic diagram of the HVPE-LED structure.

_

 : £ ¤$ í `  ¦  € Œ • l  0 A # Œ EL(electroluminescence)\  ¦ 8

£ ¤& ñ % i  .

II. ÷ m Ç ] M ö

Figure 1“ É r HVPE-LED ½ ¨› ¸_  — ¸d ” • ¸\  ¦ ˜ Ð# Œï  r  . ‘ : r



7 Hë  H \ " f  6   x ô  Ç $ í  © œZ O “ É r LPE(liquid phase epitaxy) ü <

HVPEZ O `  ¦   ô  Ç ™ D ¥ ½ + ˙ èÛ ¼ HVPE ~ ½ ÓZ O s  . LPE $ í  © œ Z O

_   â Ä º $ í  © œ– Ð\ " f  ™ è ± ú “ É r 6   xÖ 6 x& h `  ¦ t   H F K5 Å q

`

 ¦ 6   x B – Ð “ ¦ s  כ \  $ 3 Ø  ¦| ¨ c Ó ü t| 9 `  ¦ 0 l q # Œ “ ¦“ : r 8 £ ¤ \ 

"

é

¶ « Ñ   & ñ `  ¦ Z  ~ “ ¦ $ “ : r 8 £ ¤ \  l ó ø Í   & ñ `  ¦ Z  ~   6   x K • ¸

 Z  }“ É r / B M \ " f ± ú “ É r / B M Ü ¼– Ð   & ñ F « Ñ_  S X ‰ í ß –`  ¦ { 9 Ü ¼& 

~ Ã

Ì} Œ •`  ¦ $ í  © œô  Ç . 7 £ ¤, $ í  © œ 5 Å q • ¸  H l ó ø Íõ  6   x| 9 ç ß –_  “ : r

•

¸ \  _ K    & ñ ÷ &>   ) a  . # Œl \  HVPEZ O `  ¦ ] X 3 l q r 

&

 6   x B \  K { © œ   H Ga 6   xÓ  o\  “ ¦^ ‰_  • ¸ˆ  à Ô Ó ü t| 9 s 
 3-47 á ¤ " é ¶ ™ è_  F « Ñ\  ¦ f ” ] X  ' ‘ ô  Ç ˜ Ðà Ô\  ¦ ì ø Í6 £ x› ' a ? / Ò\ 



© œ‚ à Ìr †   . s Ê ê [ O & ñ  ) a “ : r • ¸\ " f Ÿ í or &  î ß –& ñ  o  ) a



© œI \ " f \ P ì  r K ü <  o† < Æ& h “   ì ø Í6 £ x`  ¦ : Ÿ x K  $ í  © œ >   ) a



 [23].

HVPE-LED _  ½ ¨› ¸  H (0001)   s # Q 0 A\  $ í  © œ  ) a n-GaN l ó ø Í`  ¦  „ ½ ÓÜ ¼– Ð RF Û ¼( ' \  ¦ s 6   x # Œ €  • 3000 Ù ¿ ºa _  SiO

\  ¦ 7 £ x ‚ Ã Ì “ ¦ ‚  × þ ˜$ í  © œ`  ¦ 0 AK  „  + þ A& h “   photo-lithography ~ ½ ÓZ O Ü ¼– Ð " é ¶+ þ A  Û ¼ß ¼ J ‡  `  ¦ _ þ vd ”  d ”  y

Œ

• % i  . d ” y Œ •ô  Ç " é ¶+ þ A J ‡  \     DH½ ¨› ¸– Ð ‚  × þ ˜$ í



© œ % i   H X < & h 8 £ x í  H " f x 9  Ó ü t| 9 “ É r Te s  • ¸i ç  ) a n-type AlGaN8 £ x,  Ö ¸$ í % ò % i  InAlGaN8 £ x, Mg s  • ¸i ç  ) a p-type AlGaN8 £ x, Mg s  • ¸i ç  ) a p-type GaN s  . Alõ  Ins  ' ‘ 

  ) a Ga ™ D ¥ ½ + ˙ èÛ ¼\  ¦ HVPE Õ þ ›! Q ? / Ò\  – Ð` ç % i “ ¦ î  r ì

ø ÍÛ ¼– Ѝ  H N

\  ¦ f  Ë  9Å Ò% 3  . HCl\  _ K  + þ A$ í  ) a ™ D ¥ ½ + Ë GaCl

ü < NH

  H $ í  © œ % ò % i Ü ¼– Ð f  Ë  Q [ þ t # Qç ß – . HClõ  NH

_  Û ¼Ä »| ¾ ӓ É r y Œ •y Œ • 20 sccm, 800 sccmÜ ¼– Ð [ O & ñ 

% i  .

Fig. 2. Cross-sectional SEM image of HVPE-LED with InAlGaN active layer.

LED : £ ¤$ í _     o\  ¦ › ¸  l  0 A # Œ, Alõ  Gas  ™ D ¥

½

+ ˝ ) a F K5 Å q ™ èÛ ¼\  In`  ¦ 0.1 g \ " f 0.5 g t  7 £ x r (  “ ¦

™

èÛ ¼ % ò % i õ  $ í  © œ % ò % i _  “ : r • ¸  H y Œ •y Œ • 900

C ü < 1090

C

–

Ð Ä »t  % i  . s  M : Al_  € ª œ“ É r 0.6 g Ü ¼– Ð “ ¦& ñ % i Ü ¼ 9 Al

Ga

N Ü ¼– Ð ˜ Ѐ Œ ¤`  ¦ M : › ¸$ í x  H 0.3 & ñ • ¸– Ð 8 £ ¤& ñ ÷ &

% 3  .

Al l ì ø Í_   o½ + ËÓ ü t“ É r { 9 ì ø Í& h Ü ¼– Ð q “ §& h  Z  }“ É r $ í  © œ“ : r • ¸

\

 ¦ € 9 כ ¹– Ð   H X < s   H 7 £ x ‚ Ã Ì r Û ¼% 7 ›s 
 ™ èÛ ¼ Û ¼ ? / Ò

\

 ï ß –À Ó   H O Ô  ¦í  HÓ ü t[ þ t – Ð “   # Œ ~ à Ì} Œ • $ í  © œ r , O $ í ì  r s

 † < ÊÄ » | ¨ c à º e ” l  M :ë  H s  . Õ ª Q
 In l ì ø Í_   o½ + ËÓ ü t“ É r In › ¸$ í `  ¦ 7 £ x r v “ ¦ In-N   ½ + Ë_  K o \  ¦ y Œ ™™ èr v l  0

A # Œ Z  }“ É r ì  r · ú šõ  ± ú “ É r $ í  © œ“ : r • ¸\  ¦ € 9 כ ¹– Ð ô  Ç  [24].



© œ ì  r o \  ¦ ~ 1 >  l  0 A # Œ € 9 כ ¹ô  Ç Z  }“ É r “ : r • ¸  H ¢ ¸ô  Ç é ß –

 

& ñ  © œI _  ½ + Ë$ í % ò % i `  ¦ V , y   H X < ´ òõ & h s  . „  F G“ É r e-beam evaporator\  ¦ s 6   x K  Cr/Ni/Au (150/150/500˚ A)

\

 ¦ 7 £ x ‚ Ã Ì % i “ ¦  Û ¼ß ¼ J ‡  @ /– Ð lift-off ô  Ç + ', ] X 8 ú ¤ $ † ½ Ó

`

 ¦ ± ú Æ ғ ¦ alloy l  0 A # Œ 600

C \ " f 5ì  r ç ß – \ P % ƒo  

% i  .

III. + s ÇÊ Ý õ m Í w Š²  o

Figure 2  H  © œ“ : r \ " f HVPE-LED_  é ß –€  `  ¦ 8 £ ¤& ñ ô  Ç SEM  ”  s  . InAlGaN 8 £ x`  ¦  Ö ¸$ í 8 £ x Ü ¼– Ð  6   x ô  Ç DH

½

¨› ¸_  8 ú x ¿ ºa   H 4.5 ¼m s % 3  .

‘

: r  7 Hë  H \ " f  H In € ª œ\    É r InAlGaN 8 £ x _  : £ ¤$ í    o

\

 ¦ › ' a ¹ 1 Ï l  0 A # Œ In`  ¦ „  ) € ' ‘  t  · ú §“ É r AlGaN8 £ x

`

 ¦ † < Êa  8 £ ¤& ñ # Œ Õ ª : £ ¤$ í `  ¦ q “ § % i  .  Ö ¸$ í 8 £ x ? /\ " f Al õ  In_  € ª œ`  ¦ · ú ˜ ˜ Ðl  0 AK  EDSü < XPS\  ¦ 8 £ ¤& ñ % i 



. InAlGaN 8 £ x _   o† < Æ& h  › ¸$ í “ É r EDS\  ¦ : Ÿ x K  · ú ˜ à º e ” 

% 3  .

Figure 3“ É r • ¸i ç ÷ &t  · ú §“ É r GaN 0 A\  $ í  © œ  ) a InAlGaN 8

£

x _  é ß –€  \ " f 8 £ ¤& ñ  ) a Al _  atomic percent\  ¦
  · p .

In _  € ª œs  7 £ x † < Ê\     Al_  peak  © œ@ /& h Ü ¼– Ð y Œ ™™ è

†

< Ê`  ¦ · ú ˜ à º e ”  . InAlGaN_  › ¸$ í `  ¦  8¹ ¡ ¤ & ñ x 9  >  · ú ˜

Fig. 3. Al atomic percent as a function of In quantity in InAlGaN layers.

Fig. 4. XPS spectra of (a) AlIn(0.5g)GaN and (b) Al2p peak, (c) In3d peak spectra of InAlGaN layer.



˜ Ðl  0 A # Œ XPS\  ¦ 8 £ ¤& ñ % i  . s \  ¦ 0 A # Œ  6   x ) a Ò 

re  ¦“ É r • ¸i ç ÷ &t  · ú §“ É r GaN \  AlGaNõ  InAlGaN`  ¦ y Œ • y

Œ

• $ í  © œô  Ç Ò  re  ¦ s  .

Figure 4 (a)  H AlIn(0.5g)GaN 8 £ x _  XPS 8 £ ¤& ñ   õ \  ¦

  · p . (b)ü < (c) Õ ªa Ë >“ É r binding energy \    H   # Œ y

Œ

•y Œ • Alõ  In_  peak\  ¦  [ jy 
 ? /% 3  . XPS 8 £ ¤& ñ r

 Ga2p_  photoelectron“ É r 1144/1117eV, O1s  H 531eV, N1s  H 398eV, Al2p  H 73eV, In3d  H 448eV \ " f S X ‰ “  ½ + É Ã

º e ”  .

EDS ü < XPS 8 £ ¤& ñ   õ , In_  € ª œ\     Al_  atomic percent     o   H  כ Ü ¼– Ð S X ‰ “   ) a  . s   H In s  7 £ x † < Ê

Fig. 5. EL spectra of the white LED (Iop=20 mA) with (a) Al(0.6 g)GaN LED and (b) In(0.3 g)Al(0.6 g)GaN LED.

\

    Al › ¸$ í q  y Œ ™™ è # Œ „  + þ A& h “   4" é ¶  o½ + ËÓ ü t _    

&

ñ $ í  © œ + þ AI \  ¦ ˜ Ð# ŒÅ ғ ¦ e ” 6 £ §`  ¦ · ú ˜ à º e ”  . Z  }“ É r “ : r • ¸\ 

"

f InAlGaN 8 £ x s  $ í  © œ÷ &  H 1 l x î ß – In_  € ª œs  7 £ x † < Ê\   



 Al_  " é ¶  [ þ t“ É r ì  r í ß – ⠖ Ð ² ú ˜ f ” Ü ¼– Ð+ ‹ Al atomic percent  ×  ¦% 3  “ ¦ Ò q ty Œ •÷ & 9 [25,26] s   H XRD 8 £ ¤& ñ `  ¦ :

Ÿ

x # Œ & ñ S X ‰ ô  Ç › ¸$ í `  ¦ ½ ¨K   S X ‰ “  ½ + É Ã º e ” Ü ¼o   ó ø Íé ß –

 ) a  .

LED ™ è  ] j Œ • Ê ê µ 1 Ï F  g : £ ¤$ í `  ¦ S X ‰ “   l  0 A # Œ z  ´“ : r

\

" f Å Ò{ 9 „  À Ó 20 mA\  ¦ f  Ë  9ï  r + ' EL spectrum`  ¦ 8 £ ¤& ñ

% i  . 8 £ ¤& ñ   õ  q “ §& h  î ß –& ñ & h “   µ 1 Ï F  g: £ ¤$ í `  ¦ ˜ Ð% i Ü ¼ 9, µ 1 Ï F  g y © œ• ¸  H 8 £ ¤& ñ ½ + É Ã º \ O % 3 Ü ¼
 ¹ ¢ ¤ î ß –Ü ¼– Ð S X ‰ “    0

p x % i  .

Figure 5  H AlGaN LED ü < InAlGaN LED_  EL Û ¼& 7 ˜à Ô

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