BiSbTe 3 / T # a U c lT c l8 ý »ì Å] k ùV ê s 4 Ò Å ù p § ü X ¢ M m8 ý »ì Å% iP
-
! H) ç | ¡
ô
Dz D G õ < Æl Õ ü t ½ ¨" é ¶ ~ à Ì} F « Ñ ½ ¨G ' p' , " fÖ ¦ 130-650; ¦ 9@ / < Æ § l / B N < Æ Ò, " fÖ ¦ 136-791
+ ä
6 0 ÷ 7 B · * × <) o . > · » . > ç ¡ ∗
ô
Dz D G õ < Æl Õ ü t ½ ¨" é ¶ ~ à Ì} F « Ñ ½ ¨G ' p' , " fÖ ¦ 130-650
®
£( å - ! H
¦ 9@ / < Æ § l / B N < ÆÂ Ò, " fÖ ¦ 136-791 (2008¸ 1 Z 4 21{ 9 ~ Ã Î6 £ §)
BiSbTe
3\ x ~ à Ì} ` ¦ Ä »l F K5 Å q o < Æ7 £ x à ÌZ O (MOCVD)Ü ¼ Ð (0001) Sapphirel ó ø Í 0 A\ $ í © % i .
:
x © & h s # Q l ó ø Í_ [ j' x 9 \ g Aõ & ñ ` ¦ 5 g $ í © ) a BiSbTe
3~ Ã Ì} _ ³ ð + þ A © É r y + þ A + þ A I
1 p x _ Ô ¦ ½ ©g Ë :ô Ç & ñ w n ` ¦ í < Ê H + þ A © ` ¦ ? /% 3 Ü ¼ $ í © l ó ø Í` ¦ ³ ð % o < ÊÜ ¼ Ð+ $ í ©
)
a ~ à Ì} _ ³ ð + þ A © ` ¦ ß ¼> > h r ~ ´ à º e % 3 . s H ³ ð % o \ ¦ : x # l ó ø ͳ ð \ p [ j < Ê` ¦ + þ
A$ í r & íl ~ Ã Ì} $ í © r Ù þ Ò q t$ í s 6 x s ¸2 ¤ % i l M :ë H Ü ¼ Ð K $ 3 ÷ &% 3 . s Qô Ç ³ ð % o l Z O
É r $ í © ) a ~ à Ì} _ \ P : £ ¤$ í \ ß ¼> % ò ¾ Ó` ¦ z u t · ú § ¤Ü ¼ 9 " f ª ô Ç ~ à Ì} + þ A \ P è _ ] j
\ 6 £ x6 x| ¨ c à º e ` ¦ כ Ü ¼ Ð l @ / ) a .
PACS numbers: 07.79.Lh, 68.55.-a
Keywords: Morphology, Atomic Force Microscope, \ P F « Ñ, MOCVD
I. " e  ] Ø
"
f Ð É r F « Ñ_ ª é ß ç ß \ : r ¸ e ` ¦ M : · ú s µ
1 ÏÒ q t H Seebeck ´ òõ \ ¦ s 6 x H \ P µ 1 Ï (thermo- electric power generation) õ % i Ü ¼ Ð f À Ó À Ó\ ¦ f Ë 9Å Ò
% 3
` ¦ M : ª é ß ç ß \ : r ¸ µ 1 ÏÒ q t H Peltier ´ òõ \ ¦ s 6
x H \ P Í ty (thermoelectric cooling)\ ' a ô Ç ½ ¨
H þ j H [ þ t # Q F Ò q t \ -t l Õ ü t õ ` \ -t rà º\ @ / ô
Ç ' a d s ¦ ¸÷ & " f & h Ö ¸ µ 1 Ïy s À Ò# Qt ¦ e [1, 2]. & ³F © 6 x o÷ &# Q 6 x ÷ & ¦ e H \ P è H Z O ß ¼+ þ A Ü
¼ Ð ] j ¸÷ & ¦ e Ü ¼ & h è+ þ A o, ~ à Ì} o, ¦$ í 0 p x o
÷
& H ~ ½ Ó ¾ ÓÜ ¼ Ð ½ ¨> hµ 1 Ïs s À Ò# Q| 9 כ Ü ¼ Ð # .
¸½ ¨ ¸^ \ ¦ s 6 x ô Ç \ P èF _ $ í 0 p x t à º ¾ Ó © \ ' a ô
Ç s : r& h [ O s ] jr ) a s Ê ê Ã º ¸p ' Å Òl _ Bi
2Te
3/Sb
2Te
3 í ½ ¨ ¸_ \ P èF H Õ ª $ í 0 p x t à º
2.4 Ð l > r _ èF \ q K S \ l & h Ü ¼ Ð 7 £ x % i [3, 4].
~ Ã
Ì} + þ A \ P èF _ â Ä º é # Qo + þ AI _ èF ü < H ² ú o
½ ¨ ¸] j# Q1 p x` ¦ : x # \ P $ í 0 p x` ¦ > h r ~ ´ Ã º e Ü ¼
∗
E-mail: [email protected]
9 # _ \ -t ¨ 8 èF ü < s Ú Ôo × ¼ ½ + Ës 0 p x
< ÊÜ ¼ Ð B Ä º Ö ¸ µ 1 Ïy & ³F ½ ¨ ' × æ s . ~ Ã Ì} + þ A \ P
èF \ ¦ s 6 x ô Ç è \ ¦ ] j l 0 AK " f H ] X $ í ` ¦ t
9 \ P ¸$ í s Ä ºÃ ºô Ç l ó ø Í0 A\ $ í © H / B N& ñ ` ¦ > h µ
1 Ï # 9 7 á § 8 $ § 4 ô Ç _ l ó ø Ís כ ¹½ ¨÷ & ¦ e
.
] X
$ í ` ¦ t H Ä »o l ó ø Í0 A\ $ í © ) a \ P ~ Ã Ì} _ â Ä
º Õ ª ³ ð + þ A © s 3 " é ¶& h Ô ¦ ½ ©g Ë :& h & ñ w n ` ¦ í < Ê
¦ e # Q B Ä º Ô ¦ç H{ 9 < Ês Ð ¦÷ & ¦ e [5]. " f z
´] j è \ _ 6 £ x6 x` ¦ 0 AK " f H ³ ð + þ A © _ > h s ì ø Í
×
¼r 9 כ ¹ > ) a . : r ½ ¨\ " f H s # Q l ó ø Í 0 A\ BiSbTe
3~ Ã Ì} $ í © r ³ ð + þ A © > h ` ¦ 0 Aô Ç ½ ¨\ ¦ Ã º '
% i . s # Q l ó ø Í` ¦ KOH- Ã º6 xÓ o\ { Õ ª# Q ³ ð
%
o \ ¦ < ÊÜ ¼ Ð+ ³ ð + þ A © ` ¦ ß ¼> > h r ~ ´ Ã º e % 3 Ü ¼ 9 s Qô Ç ³ ð + þ A © > h l ½ ¨\ ¦ ~ Ã Ì} $ í © r íl Ù þ Ò q
t$ í õ ' aº # [ O " î ¦ % i .
II. ÷ m Ç] M öU ê s0 n É
Thomas Swan \ " f ] j ô Ç Ã º¨ î ì ø Í6 £ x ' a d MOCVD
© q \ ¦ s 6 x # © · ú \ " f BiSbTe
3~ Ã Ì} ` ¦ $ í © r ( .
-364-
- telluride)\ ¦ y y 6 x % i . : r ¸\ É r y Ä »l F K 5
Å
q o½ + ËÓ ü t _ ¨ î + þ A 7 £ x l · ú É r 6 £ § õ ° ú s ³ ð & ³ ) a .
[(CH
3)
3Bi]; LoGP (mmHg) = 7.630 − 1817/T (K) [(C
2H
5)
3Sb]; LogP (mmHg) = 3.904 − 2183/T (K) [(C
3H
7)
2T e]; LogP (mmHg) = 8.288 − 2309/T (K)
F
K5 Å q Ä »l o½ + ËÓ ü t _ ¨ î + þ A 7 £ x l · ú É r ½ Ó : r ¸_ : r ¸\ ¦ ] j
#
Q < ÊÜ ¼ Ð+ ¸] X % i . $ í © × æ ì ø Í6 £ x ' a Ü ¼ Ð Ä »{ 9 ÷ & H Bi, Sb x 9 Te_ D ¥ ½ + Ëq H TMBi ü < TESb_ 7 £ x l · ú õ Ä »
|
¾ Ó (flow rate)\ _ K ¸] X ÷ &% 3 . ì ø Í6 £ x ' a ? /_ Te ì r · ú
É r 6 × 10
−4l · ú Ü ¼ Ð ¦& ñ % i Ü ¼ 9 (Bi
1−xSb
x)
2Te
3~ Ã Ì }
_ ¸$ í x H ì ø Í6 £ x ' a Ü ¼ Ð Ä »{ 9 ÷ & H F K5 Å q Ä »l Ó ü t TMBi x 9
TESb_ ì rÖ ¦ Ð ] j# Q ÷ &% 3 . : r z ´+ « >\ " f BiSbTe
3\
¦ $ í © l 0 Aô Ç ì rÖ ¦ É r 0.3 Ü ¼ Ð z ¤ . VI/V7 á ¤ D ¥
½
+ Ëq Ö ¦ (R
V I/V) É r 3 Ü ¼ Ð # $ í © × æ ~ Ã Ì} Ü ¼ ÐÂ Ò' 7 £ x µ
1 Ï÷ & H Te _ ª ` ¦ ÐØ æ ¦ % i [6].
l
ó ø ÍÜ ¼ Ð H (0001) s # Q J ?s ( \ ¦ 6 x % i
. s # Q l ó ø Í É r Ä »l Ó ü t ] j \ ¦ 0 A # TCE (trichloroethylene), [ j : r, B jò ø Í` ¦ í H Ü ¼ Ð [ j' ô Ç Ê ê S ! í
ß , í ß 6 xÓ o (3:1=H
2SO
4: H
3PO
4) Ü ¼ Ð 15 ì r ç ß \ g A
% i . \ g Aô Ç l ó ø Í É r 0.3 % KOH Ã º6 xÓ o\ { Õ ª# Q ³ ð
% o \ ¦ ' % i . [ j' x 9 \ g A õ & ñ ` ¦ 2 ; l ó ø Íõ ³ ð
% o \ ¦ 2 ; l ó ø Í` ¦ 1 l x r \ ì ø Í6 £ x ' a \ V , ¦ $ í © ô Ç Ê ê
³
ð + þ A © ` ¦ ' a ¹ 1 Ï < ÊÜ ¼ Ð+ l ó ø Í_ ³ ð % o ´ òõ \ ¦ ¶ ú ( R
Ð ¤ .
AFM (Dimension TM 3100) x 9 F g < Æ & ³p â ` ¦ s 6 x
# $ í © ) a ~ Ã Ì} _ ³ ð + þ A © ` ¦ ' a ¹ 1 Ï % i . $ í © ) a \ P
èF ª é ß \ : r ¸ \ ¦ " f H · ú y © \ ¦ :
x # Seebeck > Ã º\ ¦ 8 £ ¤& ñ % i .
III. + s ÇÊ Ý õ m Í ß e È º
FIg. 1 _ (a), (b)\ s # Q l ó ø Í x 9 ³ ð % o \ ¦ ' ô
Ç l ó ø Í 0 A\ 2 µm ¿ ºa Ð $ í © ) a BiSbTe
3~ Ã Ì} _ F g < Æ
&
³p â ' a ¹ 1 Ï ` ¦ ? /% 3 . Õ ªa Ë >\ " f Ð1 p w s : x ©
&
h [ j' x 9 \ g Aõ & ñ ` ¦ 2 ; l ó ø Í 0 A\ $ í © ) a ~ Ã Ì} _
³
ð + þ A © É r B Ä º Ô ¦ç H{ 9 9 $ í © s { 9 # Q t · ú § É r Â Ò ì
r ¸ ' a ¹ 1 Ï÷ &% 3 . s Qô Ç ~ à Ì} _ \ P : £ ¤$ í É r 1 l x{ 9 r « Ñ
\
" f ¸  Òì r& h Ü ¼ Ð B Ä º Ô ¦ç H{ 9 # F & ³$ í e H õ
\
¦ Ð# Å Òt · ú § ¤ . s ü < H ² ú o KOH- Ã º6 xÓ oÜ ¼ Ð ³ ð
% o \ ¦ ' ô Ç l ó ø Í0 A\ $ í © ) a ~ Ã Ì} É r B Ä º ç H{ 9 >
Fig. 1. Surface morphologies showing (a) a three- dimensional facet-grown BiSbTe
3film on a sapphire sub- strate and (b) a smooth, mirror-like BiSbTe
3film on surface-treated sapphire substrate.
$ í
© ÷ &% 3 Ü ¼ 9 r & h Ü ¼ Ð Ö ¦ õ ° ú É r + þ A © ` ¦
? /% 3 .
s
© _ z ´+ « >` ¦ : x # ^ ¦ M : l ó ø Í_ ³ ð % o $ í ©
)
a ~ Ã Ì} _ ³ ð + þ A © \ ß ¼> % ò ¾ Ó` ¦ p ' ¬ I6 £ §` ¦ · ú Ã º e
. s H ¿ º t ' a& h \ " f K $ 3 ÷ &# Q | 9 Ã º e . Ä º ³ ð
% o r Ä »{ 9 ) a º ú µ ¢ § s : r s ~ Ã Ì} $ í © s 6 x s ¸2 ¤
% i ³ ð % o õ & ñ \ " f s p ~ Ã Ì} $ í © s 6 x s ¸ 2
¤ H o + þ A$ í ÷ &% 3 ` ¦ 0 p x$ í s . s Qô Ç z ´+ « >& h
õ \ ¦ 7 á § 8 & ñ S X > s K l 0 AK " f : r z ´+ « >\ " f H l
ó ø Í_ ³ ð % o r ç ß ` ¦ Ã º Ð # ~ Ã Ì} $ í © s { 9 # Q
H íl _ ³ ð + þ A © ` ¦ ' a ¹ 1 Ï # Ð ¤ . s \ ¦ : x # l
ó ø Í% o \ É r ³ ð + þ A © > h B j m 7 £ §` ¦ ¦
% i .
Fig. 2 H ³ ð % o \ ¦ t · ú § É r l ó ø Í x 9 ³ ð % o \ ¦ '
ô Ç l ó ø Í` ¦ 1 l x r \ ì ø Í6 £ x ' a \ V , ¦ 10 íç ß MOCVD $ í
© ` ¦ ' ô Ç Ê ê AFMÜ ¼ Ð ' a ¹ 1 Ïô Ç ~ Ã Ì} _ ³ ð + þ A © s
. : r z ´+ « >\ " f ~ Ã Ì} _ $ í © 5 Å q ¸ Ð > í ß % i ` ¦ M : 10 í ç
ß ~ Ã Ì} $ í © ` ¦ ½ + É â Ä º Õ ª ¿ ºa H 6 nm & ñ ¸s . Fig.
2 \ " f ^ ¦ M : l ó ø Í% o \ ¦ ' t · ú § É r r ¼ # _ â Ä º íl
y + þ A + þ AI _ ] Y & ñ w n Ü ¼ Ð s À Ò Ù þ Ò q t$ í s B Ä º Ô ¦ ½ © g Ë
:& h Ü ¼ Ð { 9 # Qz ¤6 £ §` ¦ · ú Ã º e . ì ø Í \ l ó ø Í% o \ ¦ ô Ç r
¼ # _ â Ä º Ñ ü æ H ¸ ª _ Ù þ Ò q t$ í s ç H{ 9 ô Ç ì r í\ ¦ s À Ò
¦ e 6 £ §` ¦ · ú Ã º e .
l
ó ø Í_ o < Æ& h % o \ O s ~ Ã Ì} $ í © s s À Ò# Qt í l
3 " é ¶& h Ù þ Ò q t$ í s Á º 0 A & h Ü ¼ Ð { 9 # Q ^ & h Ü ¼
Ð { 9 & ñ ô Ç ~ ½ Ó0 A\ ¦ Ä »t t 3 l w ¦ e Ü ¼ 9 " f s Ê ê
~ Ã
Ì} $ í © s ' ÷ & 8 ¸ $ í © s s À Ò# Qt t · ú § É r Â Ò ì
r s H ³ ð + þ A © ` ¦ Ð כ Ü ¼ Ð # . ¢ ¸ô Ç
íl Ù þ Ò q t$ í x 9 ¸ H ³ ð % o \ ¦ ' ô Ç l ó ø Í\ " f Z 41 p x y
p
u` ¦ · ú Ã º e Ü ¼ 9 s H KOH % o ~ Ã Ì} $ í © r Ù þ Ò q t
$ í
s 6 x _ ô Ç o \ ¦ ] j/ B N % i 6 £ §` ¦ _ p ¦ e . 7 £ ¤,
Fig. 2. AFM images of BiSbTe
3films at the initial growth stage (a) on (0001) sapphire substrate and (b) on surface-treated sapphire substrate. All samples were grown for 10 seconds.
Fig. 3. AFM images of (a) a sapphire substrate and (b) a sapphire substrate whose surface had been treated for 60 min.
l
ó ø Í_ KOH % o \ ¦ : x # íl Ù þ Ò q t$ í o \ ¦ ] j/ B N ô Ç
כ
s ^ & h Ü ¼ Ð ³ ð + þ A © ` ¦ ¾ Ó © r õ \ ¦ · p
כ
Ü ¼ Ð # .
Fig. 3 É r [ j' x 9 \ g Aô Ç s # Q l ó ø Í x 9 s \ ¦ 60ì r ç
ß KOH Ã º6 xÓ o\ " f ³ ð % o \ ¦ ô Ç â Ä º_ ³ ð + þ A © ` ¦ AFM Ü ¼ Ð ' a ¹ 1 Ïô Ç s . ³ ð % o \ ¦ t · ú § É r l ó ø Í _
â Ä º Fig. 3 (a)\ " f · p כ õ ° ú s B Ä º L : F M ô Ç ³ ð
` ¦ ? / ¦ e 6 £ §` ¦ · ú Ã º e . o < Æ& h % o \ ¦ ' ô Ç l
ó ø Í_ â Ä º Fig. 3 (b)\ " f Ð כ % ! 3 ¸p ' ß ¼l _
´ ú § É r Ó ü t o & h < Ê[ þ t s µ 1 ÏÒ q t < Ê` ¦ · ú Ã º e . s H
s # Q l ó ø Í` ¦ KOH % o \ ¦ < ÊÜ ¼ Ð" f s # Q l ó ø Í\
?
/] j ) a 0 A 1 p x \ " f  Òì r& h Ü ¼ Ð $ d y s ÷ &% 3 l M : ë
H \ \ u i ± (etch pit)1 p x s + þ A$ í ÷ &% 3 l M :ë H Ü ¼ Ð #
[7]. s Qô Ç \ u i ± 1 p x \ " f_ ³ ð \ -t H ¨ î ¨ î ô Ç /
B
M \ " f Ð H p u Ü ¼ Ð Ù þ Ò q t$ í s 6 x s ô Ç o Ð 6 x| ¨ c Ã
º e . { 9 ì ø Í& h ~ Ã Ì} $ í © B j& m 7 £ § \ Ø Ô ¨ î ¨ î ô Ç l
ó ø ͳ ð Ð < Ê` ¦ l ó ø ͳ ð 7 £ ¤ Ö ¦Ú æÔ ¦Ú æ ô Ç ³ ð
\ " f Ù þ Ò q t$ í s 6 x s 9 s H Z } É r ³ ð \ -t \ ¦ t
¦ e l M :ë H s .
Fig. 4 H ³ ð % o r ç ß ` ¦ 1ì r, 5ì r, 20ì r, 60ì r Ü ¼ Ð y y
² ú o # 10 íç ß $ í © ô Ç BiSbTe
3~ Ã Ì} _ AFM s p t
\ ¦ Ð# ï r . ³ ð % o r ç ß s Z þ t # Q± ú Ã º2 ¤ Ñ ü æ H & ñ
Fig. 4. AFM images of BiSbTe
3films at the initial growth stage for different chemical treatment times: (a) 1 min, (b) 5 min, (c) 20 min, and (d) 60 min.
Fig. 5. Seeback Coefficient of BiSbTe
3film at the growth stage for different Temperature and Substrate.
s
& h & f ` ¦ S X ½ + É Ã º e . 20ì r s \ " f H Ñ ü æ H
& ñ [ þ t s B Ä º ¦ V , > ì r í÷ & 9 20ì r s © _ â Ä º
É
r é # Qo [ þ t s " f Ð W 1à Ô0 >ß ¼\ ¦ + þ A$ í # H é # Qo \ ¦ + þ
A$ í ¦ e .
: r z ´+ « > õ H ³ ð % o r ç ß s 7 £ x ½ + ÉÃ º2 ¤ ½ + ÉÃ º2 ¤ Ù þ
Ò q t$ í s 8 ´ ú §s { 9 # Qz ` ¦ _ p ¦ e . ë ß Ù þ Ò q t$ í s
l ó ø ͳ ð \ z e H º ú µ ¢ § s : r Ü ¼ Ð s À Ò# Q " é ¶
Y U6 \ _ _ º ú µ ¢ § 8 £ x Ü ¼ Ð ¸ Ø æì r ½ + É כ Ü ¼ Ð #
. 7 £ ¤, { 9 & ñ r ç ß s © ³ ð % o \ ¦ é ß 8 £ x ¿ ºa _ º ú µ
¢
§8 £ x s + þ A$ í ÷ &# Q 1 l x{ 9 ô Ç 0 l x ¸_ Ù þ Ò q t$ í s s À Ò# Q| 9 כ Ü
¼ Ð \ V © ÷ &# Q . : r z ´+ « > õ H Ù þ Ò q t$ í s ³ ð % o õ
&
ñ \ " f Ä »{ 9 ) a º ú µ ¢ § s : r _ ´ òõ _ ` ¦ _ p 9 ³ ð
Fig. 5 H GaAs l ó ø Í x 9 ³ ð % o ô Ç s # Q l ó ø Í` ¦
6 x # $ í © ô Ç BiSbTe
3~ Ã Ì} _ Seebeck © Ã º\ ¦ Ð# Å
Ò ¦ e . ³ ð % o ô Ç s # Q l ó ø Í 0 A\ + þ A$ í ) a ~ Ã Ì} _
\ P © Ã º H þ j@ / 230 µV/K Ð GaAs l ó ø Í 0 A\ $ í ©
)
a כ Ð ¸y 9 H ° ú כ` ¦ ? / ¦ e . s õ H l ó
ø Í_ ³ ð % o \ _ K $ í © ) a ~ Ã Ì} _ \ P : £ ¤$ í s $
÷
&t · ú § ¤6 £ §` ¦ _ p ¦ e . : r z ´+ « > õ H s
#
Q l ó ø Í_ ³ ð % o \ ¦ : x # ³ ð + þ A © s Ä ºÃ º 9 ª
| 9
_ \ P : £ ¤$ í ` ¦ t H ~ Ã Ì} ` ¦ % 3 ` ¦ Ã º e 6 £ §` ¦ _ p ô Ç
. s Qô Ç ³ ð % o l Z O Ü ¼ Ð $ í © ô Ç ~ Ã Ì} É r ~ Ã Ì} + þ A \ P
è ] j \ V , o Ö ¸6 x| ¨ c כ Ü ¼ Ð # .
IV. ~ ¿ W d l
: r ½ ¨\ " f H ³ ð % o ) a s # Q l ó ø Í` ¦ 6 x
#
BiSbTe
3~ Ã Ì} ` ¦ MOCVDZ O Ü ¼ Ð $ í © % i Ü ¼ 9 ³ ð + þ
A © > h B j m 7 £ §` ¦ ½ ©" î % i . ³ ð % o ³ ð + þ A
© > h \ % ò ¾ Ó` ¦ Å Ò H כ É r º ú µ ¢ § s : r ^ m
s # Q l ó ø Í ³ ð \ + þ A$ í ÷ & H Ó ü t o & h < Ê\ _ ô Ç כ Ü
¼ Ð ó ø Íé ß ÷ &% 3 . 1 l x{ 9 ô Ç ³ ð % o l Z O ` ¦ Ä »o l ó ø Í 0 A
\
& h 6 x % i ` ¦ â Ä º ³ ð + þ A © _ > h ´ òõ \ ¦ ' a ¹ 1 Ï ½ + É Ã º
\ O
% 3 . s H Ä »o l ó ø Í_ â Ä º q & ñ | 9 _ : r` ç ½ ¨ ¸\ ¦ 4
R ³ ð \ s # Q l ó ø Í% ! 3 < Ê` ¦ + þ A$ í t · ú § É r õ
Ð K $ 3 ÷ &# Q . ¢ ¸ô Ç \ P : £ ¤$ í ` ¦ 8 £ ¤& ñ ô Ç õ l ó
ø Í ³ ð % o H ~ Ã Ì} _ \ P : £ ¤$ í \ % ò ¾ Ó` ¦ Å Òt · ú §6 £ §` ¦
· ú
à º e % 3 .
: r ½ ¨ H õ < Æl Õ ü t Â Ò 21C á Ô : r w # Q ½ ¨> hµ 1 Ï
\ O
\ ¸ èF l Õ ü t > hµ 1 Ï \ O é ß _ ( ï× ¼ ñ 05K1501- 02010) t " é ¶ x 9 KIST l ' a ¦Ä » \ O \ _ # ½ ¨÷ &% 3 Ü
¼ 9 s \ y × ¼w n m .
Y
c p w à U Ø ô
[1] L. D. Hicks and M. S. Dresselhaus, Phys. Rev. B 47, 631 (1993).
[2] M. S. Sander, R. Gronsky, T. Snads and A. M. Stacy, Chem. Mater. 15, 335 (2003).
[3] A. Gani, F. Pascal-Delannoy, A. Boyer, A. Foucaran, M. Gschwind and P. Ancey, Thin Solid Films 303, 1 (1997).
[4] R. Venkatasubramanian, T. Colipitts, E. Watko, M.
Lamvik and N. EI-Masry, J.Crystal Growth 170, 817 (1997).
[5] A. Giani, A. Boulouz, F. Pascal-Delannoy, A. Fou- caran, A. Boyer and Thin Solid Films 315, 99 (1998).
[6] Yong-Chul Jung, Jeong-Hun Kim, Sang-Hee Suh, Byeong-Kwon Ju and Jin-Sang Kim, J. Crystal Growth 290, 441 (2006).
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Shi and H. B. Niu, J. Phys. D: Appl. Phys. 40, 1108
(2007).
Chemical Treatment of Substrates for Improving the Surface Morphology of BiSbTe 3 Thin Films on Sapphire
Sung-Do Kwon
Thin Film Materials Research Center, Korea Institute of Science and Technology, Seoul 130-650; Department of Electrical Engineering, Korea University, Seoul 136-791
Dae-yong Jung, Seok-Jin Yoon and Jin-Sang Kim
∗Thin Film Materials Research Center, Korea Institute of Science and Technology, Seoul 130-650
Byeong-Kwon Ju
Department of Electrical Engineering, Korea University, Seoul 136-791 (Received 21 January 2008)
Metal organic chemical vapor deposition has been used to grow BiSbTe
3films on (0001) sapphire substrates. Prior to growth, some of the substrates were subjected to chemical treatment. The impact of this process on the surface morphology of the resulting BiSbTe
3films was investigated.
Surface treatment of a sapphire substrates with a potassium-containing solution was shown to have a marked effect on the surface morphology of the resulting layers. In particular, BiSbTe
3layers grown on a sapphire substrate treated with a potassium-containing solution exhibited a high nucleation density at the initial growth stage, leading to a smooth and mirror-like morphology.
In contrast, the growth of films on sapphire substrates without treatment was found to result in random-sized island-like surface defects. We believe that the formation of nanoscale defects on the substrate surface during the chemical treatment may account for the observed improvement in the surface morphology. The smooth surface morphologies of BiSbTe
3films on sapphire substrates are promising for the fabrication of thin-film thermoelectric devices.
PACS numbers: 07.79.Lh, 68.55.-a
Keywords: Morphology, Atomic force microscope, Thermoelectric materials, MOCVD
∗
