ƒ ½ ¨ 7 Hë H Sae Mulli (The Korean Physical Society), Volume 57, Number 5, 2008¸ 11 Z 4, pp. 353∼356

 ƒ  ½ ¨ 7 Hë  H  Sae Mulli (The Korean Physical Society), Volume 57, Number 5, 2008¸   11 Z 4, pp. 353∼356

Si (111) M “ ˜ m ü; c V R ËX ê s” X ¢ GaN • «8 ý $ [Æ X Ø AlN ú n އ ˜ m • « ‘ ¤B s; c   \ ¥

° Ë

Ñ] K ¡X ì Ä — ¤V R Ë



™ »%
¦  ^∗

' õ

AÅ Ò@ /† < Ɠ § „   & ñ ˜ Ð/ B N † < Æ Ò, ' õ AÅ Ò 360-746 (2008¸   10 Z 4 1{ 9  ~ à Î6 £ §)

Ä

»l  o† < Æl  © œ7 £ x ‚ à ÌZ O Ü ¼– Ð $ “ : r AlN ×  æ ç ß –8 £ x`  ¦ s 6   x # Œ Si (111) l ó ø Í0 A\  GaN ~ à Ì} Œ •`  ¦ $ í  © œ “ ¦

$

“ : r AlN ×  æ ç ß –8 £ x ¿ ºa \    É r F  g † < Æ& h  : £ ¤$ í `  ¦ ƒ  ½ ¨ % i  . $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa \     GaN 8 £ x _  donor bound exciton (I

2

) x ß ¼ 0 Au ü < ì ø Íu ; Ÿ ¤ s    y Œ ™ >    † < Ê`  ¦ · ú ˜ à º e ” % 3  . Donor bound exciton x

ß ¼_     o  H stress \  _ ô  Ç ç  H\ P  x 9 • ¸    oü < › ' aº   e ” 6 £ §`  ¦ S X ‰ “   % i  . $ “ : r AlN ×  æ ç ß –8 £ x 10 nm ¿ º a

\ " f  © œ a % ~“ É r : £ ¤$ í `  ¦ % 3 % 3 Ü ¼ 9 11 K\ " f 21.1 meV _  ì ø Íu ; Ÿ ¤`  ¦ ° ú   H y © œô  Ç µ 1 Ï F  g x ß ¼\  ¦ ˜ Ð% i  .

PACS numbers: 78.55.Cr, 78.66.Fd, 62.40+i

Keywords: $ “ : r AlN ×  æ ç ß –8 £ x, ç  H\ P , z  ´o – B H (111), Ä »l  o† < Æl  © œ7 £ x ‚ à Ì

I. " e  ] Ø

þ

j   H \ , Si l ó ø ͓ É r $    o, @ /6   x | ¾ Ó o, Õ ªo “ ¦ a % ~“ É r \ P  x 9

 „  l & h  „  • ¸$ í 1 p x _   © œ& h  M :ë  H \  GaN _  $ í  © œ l ó ø ÍÜ ¼

–

Ð ´ ú §“ É r › ' a d ” `  ¦ ~ à Î š ¸“ ¦ e ”  . t ë ß –, GaN ü < Si l ó ø Í



s _   H     © œÃ º Ô  ¦{ 9 u ü < \ P Ø Ÿ ‚ ½ Ó > à º_  s – Ð “   K

 µ 1 ÏÒ q t   H GaN ç  H\ P  (crack) s  Si l ó ø Í`  ¦ s 6   x ô  Ç GaN _

 $ í  © œ\    a Ë >[  t ÷ &“ ¦ e ”  . ´ ú §“ É r ƒ  ½ ¨ [ þ t“ É r Si l ó ø Í\ 

"

f # Œ Q t  ! Q( 8 £ x (buffer layer) `  ¦  6   x # Œ “ ¦¾ ¡ §| 9 , Á

ºç  H\ P  GaN \  ¦ % 3 l  0 AK  ” ¸§ 4  % i Ü ¼
, 1 µm s  © œ_  Á º ç

 H\ P  (crack-free) GaN $ í  © œ l  ' p é ß –{ 9  ! Q( 8 £ x ë ß –Ü ¼– Ѝ  H ô

 Ç>  e ” % 3  . s ü < ° ú  “ É r s Ä »– Ð ×  æ ç ß –8 £ x (interlayer) `  ¦

¶ ú

š{ 9    H ~ ½ ÓZ O s  • ¸{ 9 ÷ &% 3 “ ¦ ×  æ ç ß –8 £ x Ü ¼– Ð $ “ : r AlN [1], SiNx [2], Õ ªo “ ¦  ×  æ8 £ x (multilayer) [3] 1 p x`  ¦ s 6   x   H

ƒ

 ½ ¨ ”  ' Ÿ ÷ &“ ¦ e ”  . Õ ª ×  æ \ " f• ¸ $ “ : r AlN ×  æ ç ß –8 £ x`  ¦ s

6   x ô  Ç $ í  © œZ O “ É r ç ß –é ß – €  " f   & ñ   † < Ê (defect) õ  ç  H\ P 

`

 ¦ 1 l x r \  ×  ¦{ 9  à º e ”   H $ í  © œZ O Ü ¼– Ð · ú ˜ 94 R e ”  . Õ ª Q

, a % ~“ É r : £ ¤$ í `  ¦ ° ú   H $ í  © œZ O e ” \ • ¸ Ô  ¦ ½ ¨ “ ¦ $ “ : r AlN

×

 æ ç ß –8 £ x $ í  © œZ O \  @ /ô  Ç ƒ  ½ ¨  H  f ”  p q   .

‘

: r z  ´+ « >\ " f  H Ä »l  o† < Æl  © œ7 £ x ‚ à ÌZ O  (MOCVD) Z O Ü ¼

–

Ð $ “ : r AlN ×  æ ç ß –8 £ x`  ¦ s 6   x # Œ Si (111) l ó ø Í0 A\  GaN

~ Ã

Ì} Œ •`  ¦ $ í  © œ “ ¦ $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa \    É r F  g † < Æ& h  :

£ ¤$ í `  ¦ › ' a ¹ 1 Ï % i  .

∗

E-mail: [email protected]

II. ÷ m Ç] M öU ê s0 n É

—

¸Ž  H GaN ü < AlN 8 £ x“ É r MOCVD (Veeco  , D180GaN)



© œq \  ¦ s 6   x # Œ $ í  © œ ÷ &% 3  . GaN $ í  © œ`  ¦ 0 AK  (111)

~

½ ӆ ¾ Ó Si (n+ þ A, 0.001Ω·cm) l ó ø Í`  ¦ s 6   x % i  . í ß – oÓ ü t s 

\ O

  H ³ ð€  `  ¦ 0 AK  à º™ è7 á x é ß – Si ³ ð€   % ƒo \  ¦ % i   [4].

GaN ü < $ “ : r AlN 8 £ x“ É r TMGa, TMAl ü < NH

3

\  ¦ ™ èÛ ¼  Û

¼– Ð H

²

\  ¦ H o # Q Û ¼– Ð  6   x # Œ 1045

^◦

C, 200 Torr ü

< 720

^◦

C, 76 Torr \ " f y Œ •y Œ • $ í  © œ % i  . AlN ! Q(  8

£

x $ í  © œ\  @ /ô  Ç / B N& ñ › ¸| “ É r   É r ë  H‰  ³\   [ jy  [ O " î ÷ &

#

Qe ”   [5]. 35 nm AlN ! Q( 8 £ x`  ¦ s 6   x # Œ 200 nm 1  GaN 8 £ x`  ¦ $ í  © œ “ ¦ Õ ª 0 A\  $ “ : r AlN ×  æ ç ß –8 £ x`  ¦ $ í  © œô  Ç Ê

ê 1.5 µm 2  GaN 8 £ x`  ¦ $ í  © œ % i  . $ “ : r AlN ×  æ ç ß –8 £ x

¿

ºa \  ¦ 5 nm, 10 nm, Õ ªo “ ¦ 20 nm – Ð    o # Œ $ í  © œ 

%

i  . $ “ : r AlN ×  æ ç ß –8 £ x`  ¦ s 6   x # Œ $ í  © œ  ) a 8 £ x _  þ j7 á x ½ ¨

›

¸ Fig. 1 \ 
 
e ”  .

$

“ : r AlN ×  æ ç ß –8 £ x ¿ ºa \    É r 2  GaN _  ç  H\ P x 9 • ¸



 H normalski ‰ & ³p  â (x50) `  ¦ s 6   x # Œ › ' a ¹ 1 Ï % i  . $ í



© œ  ) a 8 £ x _    & ñ $ í `  ¦ › ' a ¹ 1 Ï l 0 AK  X-ray rocking curve (XRC) 8 £ ¤& ñ `  ¦ % i “ ¦ F  g † < Æ& h “   : £ ¤$ í `  ¦ › ' a ¹ 1 Ï l 0 AK  11 K ∼ 300 K _  “ : r • ¸ # 3 0 A\ " f photoluminescence (PL) 8 £ ¤

&

ñ `  ¦ % i  .

III. + s ÇÊ Ý õ m Í À X Ø8 ý

$

“ : r AlN ×  æ ç ß –8 £ x ¿ ºa \    É r 2  GaN 8 £ x _    & ñ $ í

`

 ¦ · ú ˜ ˜ Ðl  0 AK  XRC 8 £ ¤& ñ `  ¦ % i  . XRC 8 £ ¤& ñ   õ 

-353-

-354- ô  Dz D GÓ ü t o † < Æ rt  “D hÓ ü t o ”, Volume 57, Number 5, 2008¸   11 Z 4

Fig. 1. Schemetic of the GaN structure with LT AlN interlayer.

Fig. 2. Crack Number of the GaN films grown on Si (111) substrate with LT AlN interlayer thickness.

—

¸Ž  H Ò  re  ¦ \ " f (002) Ä º‚  C † ¾ Ó`  ¦ ° ú   H é ß –  & ñ s  $ í  © œ H † d

`

 ¦ S X ‰ “   % i “ ¦ Fig. 2 \  (002) FWHM 8 £ ¤& ñ   õ 
 

 e ”  . $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa  7 £ x † < Ê\    , GaN 8

£

x _    & ñ $ í s  † ¾ Ó © œ H † d`  ¦ ˜ Ðs   20 nm ¿ ºa \ " f ° ú š  l

   & ñ $ í s  $  ÷ &  H  ⠆ ¾ Ó`  ¦ ˜ Ðs “ ¦ e ”  . s    õ   H $ 

“

: r AlN ×  æ ç ß –8 £ x \  e ” >  ¿ ºa  ” > r F † < Ê`  ¦
 ? / 9 10 nm

¿

ºa \ " f Si l ó ø Í\  _ ô  Ç 6 £ x§ 4  (stress) s  ¢ - a  o ÷ &% 3  

20 nm – Ð ¿ º 0 > t €  " f $ “ : r AlN ×  æ ç ß –8 £ x \  _ ô  Ç 6 £ x§ 4  s

 K 4 R
 
  H  כ Ü ¼– Ð ó ø Íé ß –  ) a  . 5 nm, 10 nm, Õ ª o

“ ¦ 20 nm _  $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa \ " f (002) FWHM

“ É

r y Œ •y Œ • 933 arcsec, 651 arcsec, Õ ªo “ ¦ 825 arcsec s % 3 



. ¢ ¸ô  Ç, XRC x ß ¼ y © œ• ¸  H (002) FWHM 8 £ ¤& ñ   õ ü <

{ 9

u   9 $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa  10 nm { 9  M :  © œ Z  }

“ É

r x ß ¼y © œ• ¸\  ¦ ˜ Г   . $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa  10 nm { 9

 M :  © œ a % ~“ É r   & ñ $ í `  ¦ ˜ Ð% i  .

Fig. 3 “ É r $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa \     $ í  © œô  Ç 2  GaN 8 £ x _  ç  H\ P x 9 • ¸\  ¦
  · p . 1  GaN ¿ ºa  5 nm, 10 nm, Õ ªo “ ¦ 20 nm { 9  M : €  • 1.5 µm $ í  © œô  Ç 2  GaN

Fig. 3. (002) X?ray rocking curves of GaN layer with LT AlN interlayer thickness.

~ Ã

Ì} Œ •\  @ /ô  Ç ç  H\ P x 9 • ¸– Ð y Œ •y Œ • 70 /cm, 5 /cm, Õ ªo “ ¦ 30 /cm s % 3  . $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa \    É r ç  H\ P  x 9 • ¸  H 5 nm { 9  M :  © œ ´ ú §“ É r ç  H\ P s  ˜ Ðs t ë ß – 10 nm ¿ ºa \ 

"

f  H  _  — ¸Ž  H ç  H\ P s    & ’   20 nm ¿ ºa  ÷ &€  



r  ç  H\ P s  › ¸F K 7 £ x    H  ⠆ ¾ Ó`  ¦ ˜ Ð% i  . s    õ \ " f

˜

Ѝ  H  % ƒ! 3  $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa _  p [ jô  Ç    o\ • ¸ GaN _  ç  H\ P x 9 • ¸  © œ{ © œy    y Œ ™ >    † < Ê`  ¦ · ú ˜ à º e ” % 3 



. 7 £ ¤, $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa     o €  " f 2  GaN _  6

£ x§ 4 s     o÷ &% 3 l  M :ë  H“    כ Ü ¼– Ð ó ø Íé ß –  ) a   [5]. s    õ 



 H XRC   õ ü < { 9 u † < Ê`  ¦ ˜ Ðs “ ¦ e ”  .

$

“ : r AlN ×  æ ç ß –8 £ x ¿ ºa  F  g † < Æ& h “   : £ ¤$ í \  p u   H % ò

†

¾ Ó`  ¦ › ' a ¹ 1 Ï l 0 AK  PL 8 £ ¤& ñ `  ¦ % i  . Fig. 4   H  © œ“ : r \ 

"

f 8 £ ¤& ñ  ) a $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa \    É r 2  GaN 8 £ x _  PL : £ ¤$ í `  ¦
 ? /“ ¦ e ”  . PL x ß ¼ 0 Au   H 5 nm - 3.376 eV, 10 nm - 3.376 eV, Õ ªo “ ¦ 20 nm - 3.385 eV # 3 0 A\  ¦

t “ ¦ e ” Ü ¼ 9 $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa \     x ß ¼ 0 Au 

 › ¸F Km ”  blue-shift ÷ &% 3  . s  PL x ß ¼ 0 Au   H   s 

#

Q l ó ø Í0 A\ " f strain relaxation  ) a GaN _  x ß ¼˜ Ð  €  • 35 ∼ 45 meV ± ú “ É r ° ú כs  [6]. ¢ ¸ô  Ç, $ “ : r AlN ×  æ ç ß –8 £ x ¿ º a

 7 £ x † < Ê\     x ß ¼ y © œ• ¸  H 7 £ x , PL FWHM “ É r & h 

&

h  y Œ ™™ è† < Ê`  ¦ ˜ Ðs   20 nm ¿ ºa \ " f x ß ¼ y © œ• ¸  H y Œ ™

™

è, PL FWHM “ É r 7 £ x † < Ê`  ¦ ˜ Ðs “ ¦ e ”  . s    õ   H · ú ¡ _

 XRC, ç  H\ P x 9 • ¸   õ ü < { 9 u  “ ¦ e ”  . PL FWHM

“

É r 5 nm - 43.7 meV, 10 nm - 38.1 meV, Õ ªo “ ¦ 20 nm - 47.1 meV `  ¦ % 3 % 3  . $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa  10 nm { 9  M

:  © œ a % ~“ É r PL : £ ¤$ í `  ¦ ˜ Ð% i  .

$

“ : r AlN ×  æ ç ß –8 £ x ¿ ºa  GaN 8 £ x _  F  g † < Æ& h  : £ ¤$ í \ \  p

u   H % ò † ¾ Ó`  ¦ 7 á §  8  [ j >  ì  r$ 3  l  0 AK  11 K “ : r • ¸

\

" f 8 £ ¤& ñ % i “ ¦ Fig. 5 \ 
 
 e ”  . — ¸Ž  H GaN r « Ñ

 ƒ  ½ ¨ 7 Hë  H  Si (111) l ó ø Í0 A\  $ í  © œô  Ç GaN 8 £ x _  $ “ : r AlN ×  æ ç ß –8 £ x1· · · – ^ ”  ü ½ © -355-

Fig. 4. PL properties of GaN layer with LT AlN inter- layer thickness at RT.

\

" f „  + þ A& h “   neutral donor bound exciton recombina- tion (I

₂

)  “  õ  ¿ º> h_  phonon replica 
 z Œ ¤ . I

2

_

 x ß ¼ 0 Au   H $ “ : r AlN ! Q( 8 £ x ¿ ºa  7 £ x \     s 1 l x (shift) ‰ & ³ © œs 
 z Œ ¤ . 5 nm, 10 nm, Õ ªo “ ¦ 20 nm $ 

“

: r AlN ×  æ ç ß –8 £ x ¿ ºa \ " f_  I

2

x ß ¼0 Au   H y Œ •y Œ • 3.461 eV, 3.458 eV, Õ ªo “ ¦ 3.468 eV % i  . 10 nm ¿ ºa _  I

2

x ß ¼ 0

Au   H Si l ó ø Í 0 A\ " f ç  H\ P  \ O s  $ í  © œô  Ç GaN ~ à Ì} Œ •_  I

²

x

ß ¼ ° ú כ“   3.457 eV \    H] X † < Ê`  ¦ ˜ Ðs “ ¦ e ” t ë ß – 5 nm ü <

20 nm ¿ ºa \ " f  H s  ° ú כ ˜ Ð   H ° ú כ`  ¦ ˜ Ðs “ ¦ e ”   [7].

s

   õ   H ~ à Ì} Œ •_  ç  H\ P – Ð “  K  GaN 8 £ x \  K ”   tensile stress  ¢ - a  o÷ &# Q
 
  H ‰ & ³ © œÜ ¼– Ð 5 nm ü < 20 nm ¿ º a

\ " f I

²

x ß ¼_  blue-shift ‰ & ³ © œs 
 z Œ ¤ [5]. { 9 ì ø Í& h  Ü

¼– Ð tensile stress ¢ - a  o÷ &€   Ó ü t| 9 _   ½ ™× ¼Ì “ ss  7 £ x  

#

ΠI

2

_  x ß ¼ 0 Au • ¸ “ ¦\  -t  A á ¤ Ü ¼– Ð s 1 l x >   ) a  .



© œ“ : r \ " fü < ° ú  s , $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa  7 £ x † < Ê\   



 x ß ¼ y © œ• ¸  H 7 £ x , PL FWHM “ É r & h & h  y Œ ™™ è† < Ê`  ¦ ˜ Ðs 



 20 nm ¿ ºa \ " f x ß ¼ y © œ• ¸  H y Œ ™™ è, PL FWHM “ É r 7

£

x † < Ê`  ¦ ˜ Ðs “ ¦ e ”  . 5 nm, 10 nm,Õ ªo “ ¦ 20 nm $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa \  @ /ô  Ç I

2

x ß ¼_  FWHM “ É r y Œ •y Œ • 23.8 meV, 21.1 meV, Õ ªo “ ¦ 23.8 meV % i  .

Fig. 6 “ É r ç  H\ P x 9 • ¸\    É r I

2

x ß ¼ 0 Au \  ¦
 ? /% 3  .

ç

 H\ P x 9 • ¸ 7 £ x † < Ê\    , I

²

x ß ¼ 0 Au  7 £ x   

y

Œ

™™ è† < Ê`  ¦ ˜ Ðs “ ¦ e ”  . s  y Œ ™™ è ‰ & ³ © œ“ É r 5 nm $ “ : r AlN

×

 æ ç ß –8 £ x ¿ ºa \ " f
 
  H  כ Ü ¼– Ð ç  H\ P \  _ K  tensile stress  ¢ - a  o H † d \ • ¸ Ô  ¦ ½ ¨ “ ¦ ×  æ ç ß –8 £ x ¿ ºa  · û ª  Si l  ó

ø Í\  _ K 
 
  H  כ Ü ¼– Ð ó ø Íé ß –  ) a  . 7 £ ¤, · û ª“ É r AlN ×  æ ç

ß –8 £ x ¿ ºa – Ð “  K  Si l ó ø Í\  _ ô  Ç tensile stress y © œ > 



Œ

•6   x`  ¦ “ ¦ Õ ª 6 £ x§ 4 `  ¦ ¢ - a  o l  0 AK  ç  H\ P s  ´ ú §s  µ 1 ÏÒ q t ô

 Ç  כ Ü ¼– Ð ó ø Íé ß –  ) a  . ç  H\ P  x 9 • ¸ 10/cm \ " f  © œ ± ú “ É r I

2

Fig. 5. PL properties of GaN layer with LT AlN inter- layer thickness at 11K.

Fig. 6. PL(I

2

) peak position variations as a function of crack number at 11K.

x

ß ¼ 0 Au \  ¦ % 3 % 3 Ü ¼ 9 s  ° ú כ“ É r Si l ó ø Í 0 A\ " f ç  H\ P  \ O s 

$ í

 © œô  Ç GaN ~ à Ì} Œ •_  I

2

x ß ¼ ° ú כ\    H] X † < Ê`  ¦ ˜ Г   .

IV. + s Ç Â ] Ø

‘

: r ƒ  ½ ¨\ " f  H MOCVD Z O Ü ¼– Ð $ “ : r AlN ×  æ ç ß –8 £ x ¿ º a

› ¸] X `  ¦ : Ÿ x K  Si l ó ø Í0 A\  “ ¦¾ ¡ §| 9  GaN ~ à Ì} Œ •`  ¦ $ í  © œ 

%

i  . $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa \     GaN _  F  g † < Æ& h  : £ ¤

$ í

s    y Œ ™ >    † < Ê`  ¦ · ú ˜ à º e ” % 3 “ ¦ 10 nm $ “ : r AlN ×  æ ç

ß –8 £ x ¿ ºa \ " f Ä ºÃ ºô  Ç F  g † < Æ& h  : £ ¤$ í `  ¦ S X ‰ “   % i  . ¢ ¸ô  Ç, s

   õ   H $ “ : r AlN ×  æ ç ß –8 £ x ¿ ºa  2  GaN $ í  © œ\  e ” 

#

Q" f ×  æ כ ¹ô  Ç % i ½ + É`  ¦ † < Ê`  ¦
  · p .

-356- ô  Dz D GÓ ü t o † < Æ rt  “D hÓ ü t o ”, Volume 57, Number 5, 2008¸   11 Z 4

Y

c p w Š à U Ø ”  ô

[1] G. Cong, Y. Lu, W. Peng, X. Liu, X. Wang and Z.

Wang, J. Crystal Growth 276, 381 (2005).

[2] K. Engl, M. Beer, N. Gmeinwieser, U. T. Schwarz, J. Zweck, W. Wegscheider, S. Miller, A. Miler, H.-J.

Lugauer, G. Br¨ uderl, A. Lell and V. H¨ arle, J. Crystal Growth 289, 6 (2006).

[3] Y. L. Tsai, J. R. Gong, Opt. Mater. 27, 425 (2004).

[4] G. S. Higashi, Y. J. Chabal, G. W. Trucks and K.

Laghavachari, Appl. Phys. Lett. 56, 656 (1990).

[5] Deok Kyu Kim, SAEMULLI (New Phys.) 54, 561 (2007).

[6] S. Chichibu, H. Okumura, S. Nakamura, G. Feuillet, T. Azuhata, T. Sota and S. Yoshida, Jpn. J. Appl.

Phys. 36, 1976 (1997).

[7] A. Strittmatter, A. Krost, M. Strassburg, V. T¨ urk, and D. Bimberg, Appl. Phys. Lett. 74, 1242 (1999).

Optical Properties of GaN on a Si(111) Substrate with a LT AlN Interlayer

Deok Kyu Kim

^∗

Division of Electronics and Information Engineering, Cheongju University, Cheongju 360-746 (Received 1 October 2008)

GaN layers were grown on silicon (111) substrates with low-temperature (LT) AlN interlayers by using metalorganic vapor phase epitaxy, and the optical properties of GaN layers were investigated as functions of the LT AlN interlayer’s thickness. By changeing the thickness of the LT AlN, we could sensitively change the peak position and the full width at half maximum (FWHM) of the donor bound exciton (I

2

) of the GaN layers. The shift in the donor bound exciton peak was relative to the crack density due to heavy stress. In the 10-nm-thick LT AlN, a strong band-edge emission, with a full width at half maximum of the bound exciton line being as low as 21.1 mev at 11 K, was observed from the GaN layer on Si(111).

PACS numbers: 78.55.Cr, 78.66.Fd, 62.40+i

Keywords: LT AlN Interlayer, Crack, Silicon (111), Metalorganic chemical vapor deposition

∗

E-mail: [email protected]