Influence of the Surface Roughness of a ZnO Layer on the Growth of a Polycrystalline Si-layer by Using an Aluminum-induced Layer-exchange

Vol. 63, No. 11, November 2013, pp. 1218∼1223

Influence of the Surface Roughness of a ZnO Layer on the Growth of a Polycrystalline Si-layer by Using an Aluminum-induced Layer-exchange

Process

W. B. Chang · S. K. Choi · S. H. Jung · J. W. Lee · J. H. Chang ^∗

Major of Applied Science, Korea Maritime and Ocean University, Busan 606-791, Korea

K. Hara · H. Watanabe · N. Usami

Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan (Received 17 September 2013 : revised 7 October 2013 : accepted 12 November 2013)

We have investigated the effect of the surface roughness of the zinc-oxide (ZnO) layer on the growth of a by using the polycrystalline-Si (poly-Si) layer Al-induced layer-exchange process. We found that the growth rate, grain size, crystallized fraction and preferential orientation were closely related to the surface roughness of the underlying ZnO layer. As the ZnO surface became rougher, the growth rate, grain size, and crystallized fraction increased, and a preferential orientation in the (100) direction appeared as well. The poly-Si layer that formed on ZnO with a root-mean-square roughness of 2.4 nm revealed a fast growth time (40 minutes), a large grain size (∼20 µm) and a high crystallized fraction (51%) with a preferential (100) orientation.

PACS numbers: 64.70.Md, 64.60.Qb, 64.70.Kb, 68.35.-P

Keywords: Aluminum-induced layer exchange, Polycrystalline Silicon, Zinc oxide, Surface roughness, Solar cell

Al-Si • «w ‹ò & ÿ V R ËX ê s; c" e ZnO ƒ »ì Å  ú m ÇM  Si + s ÇX N ËV R Ë; c Q V À W ¥ W _ Ë] ‚ §

† ç

¡ 4 w H( 8  · L |) ç V  œ · + ä ¬ £0 å  · T + ä ­ £ · † ç ¡U ‡ Ú ^∗

ô

 Dz D G K € ª œ@ /† < Ɠ § 6 £ x6   x õ † < Æ Ò,  Òí ß – 606-791

Kosuke HARA · Haruna WATANABE · Noritaka USAMI

Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan (2013¸   9 Z 4 17{ 9  ~ à Î6 £ §, 2013¸   10 Z 4 7{ 9  à º& ñ ‘ : r ~ à Î6 £ §, 2013¸   11 Z 4 12{ 9  > F  S X ‰& ñ )

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¦´ òÖ  ¦ ~ à Ì} Œ • I € ª œ„  t _  ½ ¨‰ & ³`  ¦ 0 AK  ZnO (Zinc Oxide) ~ à Ì} Œ •0 A\  Al-Si 8 £ x “ § ¨ 8 Š $ í  © œ~ ½ ÓZ O  (layer exchange method)`  ¦ s 6   x # Œ    & ñ z  ´o – B H (poly-Si)`  ¦ $ í  © œ % i  . : £ ¤ y  ‘ : r ƒ  ½ ¨\ " f  H ZnO _ 

³

ð€    } 9 l     & ñ Si   & ñ $ í \  p u   H % ò † ¾ Ó`  ¦ › ¸  % i  . ZnO ³ ð€    } 9 l \    É r    & ñ Si_ 

 

& ñ w n _  ß ¼l  (grain size), & ñ § > =~ ½ ӆ ¾ Ó    o\  ¦ $ í  © œ ×  æ ‰ & ³p  ⠛ ' a ¹ 1 Ï, Field-emission scanning electron microscope (FE-SEM)8 £ ¤& ñ õ  Electron backscatter diffraction (EBSD)`  ¦ s 6   x K  › ¸  % i  . ZnO _

 ³ ð€    } 9 l  7 £ x  ½ + É Ã º2 Ÿ ¤   & ñ  o 5 Å q • ¸ü <   & ñ w n  ß ¼l  7 £ x  % i Ü ¼ 9, (100)C † ¾ Ós  › ' a ¹ 1 Ï÷ &% 3 



.   õ & h Ü ¼– Ð ³ ð€    } 9 l  2.4 nm “   ZnO \  ¦ s 6   x # Œ 20 µm s  © œ_  { 9  ß ¼l ü < Z  }“ É r   & ñ  o• ¸ 1218

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\ 

¦ t  9 51% s  © œ_  (100) C † ¾ Ó$ í `  ¦ ° ú   H    & ñ Si ~ à Ì} Œ •s  ½ ¨‰ & ³÷ &# Q, Z  }“ É r ´ òÖ  ¦`  ¦ ° ú   H    & ñ Si

~ Ã

Ì} Œ • I € ª œ„  t _  $ í 0 p x † ¾ Ó © œ\  l # Œ½ + É Ã º e ”   H 0 p x$ í `  ¦ ] jr  % i  .

PACS numbers: 64.70.Md, 64.60.Qb, 64.70.Kb, 68.35.-P Keywords: 8 £ x “ § ¨ 8 Š $ í  © œ~ ½ ÓZ O , poly-Si, ZnO, ³ ð€   } 9 l , I € ª œ„  t 

I. " e  ] Ø

þ

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-t \  ¦ Ò q tí ß –   H X < ×  æ כ ¹ô  Ç l Õ ü t – Ð y Œ • F  g`  ¦ ~ à Γ ¦ e ” Ü ¼ 9, I

€ ª œ F  g µ 1 τ   r  © œ“ É r t è ß – 10¸  ç ß – B ¸   40% s  © œ_  Z  }“ É r

$ í

 © œÒ  ¦ s  t 5 Å q ÷ &“ ¦ e ”   [1]. l ” > r _  µ 1 τ  ~ ½ ÓZ O \  q K " f I

€ ª œ F  g µ 1 τ   r Û ¼% 7 ›“ É r  © œ@ /& h Ü ¼– Ð Z  }“ É r µ 1 τ  é ß –\  ¦  t

  H l Õ ü t – Ð, r Û ¼% 7 › ½ ¨$ í כ ¹™ è ×  æ I € ª œ F  g — ¸Ñ ý t s   © œ  H q

×  æ`  ¦ t  “ ¦ e ”  . ¢ ¸ô  Ç — ¸Ñ ý t é ß –_  ] X ì ø Í s  © œ`  ¦ l  ó

ø Ís  t  “ ¦ e ”   H ½ ¨› ¸s   [2,3]. 7 £ ¤, I € ª œ F  g µ 1 τ   r  Û

¼% 7 ›_  Z  }“ É r q 6   x“ É r I € ª œ F  g µ 1 τ  _  " é ¶ F « Ñ ÷ &  H Si l  ó ø

Í_  Z  }“ É r é ß –\ " f l “  ô  Ç  כ s   [4].   " f ‰ & ³F  Si J

?s ( _  ~ à Ì+ þ A oü < J ?s (  + þ AI      ½ ¨ + þ AI _  Si  Ö ¸ 6

  x, Õ ªo “ ¦ " é ¶ « Ñ F Ò q t 1 p x \  @ /ô  Ç ƒ  ½ ¨  Ö ¸ µ 1 Ïy  ”  ' Ÿ  ×  æ

\

 e ”  . ×  æ · © œl & h  @ /î ß –Ü ¼– Ѝ  H “ ¦• ¸_  F K5 Å q & ñ º   l Õ ü t

`

 ¦ s 6   x K  Ò q tí ß –  ) a Si`  ¦ " é ¶ « і Ð ô  Ç $ _  l ó ø Í`  ¦  Ö ¸6   x ô  Ç I

€ ª œ„  t  ] j› ¸, Si x 9   o½ + ËÓ ü t ì ø ͕ ¸^ ‰ ~ à Ì} Œ •`  ¦  Ö ¸6   x ô  Ç ~ à Ì} Œ • + þ

A I € ª œ„  t  1 p x _  ~ ½ ÓZ O • ¸ ƒ  ½ ¨ ×  æ \  e ”   [5–8].

s

ü < ° ú  “ É r # Œ Q t  ~ à Ì} Œ • I € ª œ„  t  ] j› ¸ l Õ ü t ×  æ Ò q t í

ß –é ß –\  ¦ ] X y Œ ™   H ~ ½ ÓZ O  ×  æ 
– Ð glass 1 p x õ  ° ú  “ É r $ 

_  l ó ø Í 0 A\     & ñ Si ~ à Ì} Œ •`  ¦ $ í  © œr &  I € ª œ„  t \  ¦

>

hµ 1 Ï “ ¦    H ] jî ß –s  e ”   [9, 10]. 7 £ ¤ 8 ú ¤ B  F K5 Å q`  ¦ s

6   x # Œ $ “ : r \ " f α-Si_  F   & ñ  o\  ¦ Ä »• ¸ # Œ    & ñ Si ~ à Ì} Œ •`  ¦ $ í  © œ   H · ú ˜À Òp ³ o u 8 £ x “ § ¨ 8 Š ~ ½ ÓZ O  (Aluminum- induced layer exchange; ALE) s  Õ ª כ s  . ALE  H 8 £ x “ §

¨ 8

Š (Layer exchange)‰ & ³ © œ`  ¦ s 6   x ô  Ç  כ Ü ¼– Ð Alõ  Si_  / B N Ö

6 x “ : r • ¸ (577 ^◦ C) \ " f Al õ  Sis  Ó  o © œÜ ¼– Ð    # Œ 8 £ x “ §

¨ 8

Š s  { 9 # Q
“ ¦, Õ ª   õ  α-Si s  F   & ñ  o õ & ñ `  ¦  5 g  

 

& ñ SiÜ ¼– Ð   & ñ  o ÷ &# Q Ä »o l ó ø Í 0 A\     & ñ Si~ à Ì} Œ • s

 + þ A$ í  ) a   [11]. s  Qô  Ç F   & ñ  o õ & ñ “ É r : Ÿ x  © œ à º r ç ß –

&

ñ • ¸ € 9 כ ¹  9 ] j Œ •  ) a    & ñ Si`  ¦ l ó ø ÍÜ ¼– РÒ'  ] j 

# Œ „  F G+ þ A$ í / B N& ñ `  ¦  5 g  I € ª œ„  t  ] j Œ •s  0 p x 



. ¢ ¸ô  Ç F   & ñ  o\  ¦ : Ÿ x K " f % 3 # Qt   H   & ñ w n _  ß ¼l ü <

 

& ñ  o ~ ½ ӆ ¾ Ó 1 p x“ É r ƒ  ½ ¨ Õ ªÒ  ¨Z > – Ð  Ø Ô 9  f ”  t   H s 

\

 ¦ ] j# Q½ + É Ã º e ”   H  Ž 7 £ x ) a ~ ½ ÓZ O s  ˜ Г ¦ ÷ &t  · ú §€ Œ ¤ .

‘

: r ƒ  ½ ¨  H 8 £ x “ § ¨ 8 Š ‰ & ³ © œ`  ¦ s 6   x # Œ Al õ  Si _  / B NÖ 6 x

“

: r • ¸ (577 ^◦ C) \ " f \ P % ƒo \  ¦ ”  ' Ÿ  % i  . ZnO~ à Ì} Œ •0 A\ 

∗

E-mail: jiho [email protected]

Fig. 1. (Color online) Schematic drawing of the fabrication process of poly-Si layer by the ZnO assisted aluminum-induced layer exchange process:

(a) amorphous-Si/Al/ZnO/glass stacked sample (as- deposited sample), (b) Al/poly-Si/ZnO/glass stacked sample (layer exchanged sample), (c) poly-Si/ZnO/glass (after etching of the Al layer on the surface).

"

f F   & ñ  o ”  ' Ÿ ÷ &€   ZnO³ ð€  _  % ò † ¾ ÓÜ ¼– Ð    & ñ Si _    & ñ  o õ & ñ `  ¦ ] j# Q½ + É Ã º e ”  “ ¦ ó ø Íé ß – % i Ü ¼ 9, ¢ ¸ ô

 Ç ZnO  H ¸ ú ˜ · ú ˜ 9”   È Ò" î „  F G Ó ü t| 9 s Ù ¼– Ð Z > • ¸_  „  F G + þ

A$ í / B N& ñ s  € 9 כ ¹ \ O    H & h \  ‚ à Ìî ß – # Œ ZnO\  ¦ s 6   x ô  Ç 8

£

x “ § ¨ 8 Š $ í  © œZ O \  › ' a # Œ ƒ  ½ ¨\  ¦ r  Œ • % i  . : £ ¤ y  ZnO

³

ð€  _   } 9 l  8 £ x “ § ¨ 8 Š $ í  © œ\  p u   H % ò † ¾ Ó`  ¦ › ¸  

#

Œ “ ¦´ òÖ  ¦ ~ à Ì} Œ •I € ª œ„  t  > hµ 1 Ïs  0 p x ô  Ç 8 £ x “ § ¨ 8 Š $ í  © œZ O 

`

 ¦ ] jî ß –½ + É 3 l q& h Ü ¼– Ð ƒ  ½ ¨\  ¦ ”  ' Ÿ  % i  .

II. ÷ m Ç ] M ö

‘

: r ƒ  ½ ¨\ " f  H glass l ó ø Í  © œ\  sputtering Z O Ü ¼– Ð ZnO ( ¿ ºa  ∼100 nm, $ í } Œ •5 Å q • ¸ ∼1.6 nm/sec)\  ¦ 7 £ x ‚ Ã Ì % i Ü ¼ 9, Û ¼( '  Õ þ ›! Q ? / Ò_  · ú š§ 4 `  ¦    or &  ZnO ³ ð€  _    } 9

l \  ¦    or (   . ¢ ¸ô  Ç ZnO 0 A\   H \ P 7 £ x ‚ à ÌZ O Ü ¼– Ð 130 nm ¿ ºa _  Al `  ¦ \ P 7 £ x ‚ Ã Ì % i “ ¦ Õ ª 0 A\  Û ¼( ' \  ¦ s 6   x

# Œ €  • 200 nm ¿ ºa _  α-Si `  ¦ $ í } Œ •r (   . ] j Œ •  ) a r 

«

э  H $ í  © œõ & ñ `  ¦ F  g † < Ɖ & ³p  â Ü ¼– Ð › ' a ¹ 1 Ͻ + É Ã º e ”   H \ P % ƒ o

– Ð\  ¦ s 6   x # Œ 8 £ x “ § ¨ 8 Š $ í  © œ % i  .

Figure 1“ É r s  Qô  Ç 8 £ x “ § ¨ 8 Š $ í  © œ`  ¦ : Ÿ x K  α-Si 8 £ x õ  Al 8

£

x s  " f– Ð “ § ¨ 8 Š ÷ &# Q    & ñ Si s  $ í  © œ÷ &  H õ & ñ `  ¦
 



· p  כ s  . Fig. 1(a)  H ALE / B N& ñ `  ¦ l  „  _  r ¼ # _  ½ ¨

›

¸\  ¦
  · p  כ Ü ¼– Ð α-Si/Al/ZnO/glass_  & h 8 £ x + þ AI \  ¦

t “ ¦ e ”  . s  Qô  Ç r ¼ # `  ¦ 1L/min Ä »| ¾ Ó_   Ø ÔŒ 4 H ì  r 0

Al  › ¸|  \  Al õ  Si _  / B NÖ 6 x “ : r • ¸“   577 ^◦ C _  “ : r • ¸

\

" f 3r ç ß – 1 l x î ß – \ P % ƒo   9 F   & ñ  o ÷ &  H õ & ñ `  ¦ › ¸



 % i  . Fig. 1(b)  H \ P % ƒo  Ê ê Al õ  α-Si 8 £ x s  " f– Ð “ §

¨ 8

Š ÷ &# Q F   & ñ  o ”  ' Ÿ  ) a    & ñ Si _  & h 8 £ x ½ ¨› ¸\  ¦
 

 · p  כ s “ ¦, Fig. 1(c)  H 8 £ x “ § ¨ 8 Š á Ԗ Ð[ jÛ ¼_    õ \  ¦ S X ‰

“

  l  0 AK  ³ ð€  \  ï ß –À Óô  Ç Al 8 £ x`  ¦ HCl 6   xÓ  o`  ¦ s 6   x 

#

Œ 40 ^◦ C \ " f 5ì  r ç ß – d ” y Œ • “ ¦ ï ß –À Ó Al 8 £ x`  ¦ z  ´“ : r \ " f HF

\

 ¦ s 6   x # Œ ¢ - a„  y  ] j  ô  Ç r « Ñ\  ¦
  · p .

ZnO $ í } Œ • Ê ê r « Ñ ³ ð€  _   } 9 l   H " é ¶  § 4 ç ß – ‰ & ³p  â (Atomic force microscopy: AFM) Ü ¼– Ð ¨ î Ù þ ¡ . ¢ ¸ô  Ç \ P 

%

ƒo  (annealing) õ & ñ ×  æ \  F  g † < Æ ‰ & ³p  â `  ¦  6   x ô  Ç z  ´r  ç

ß – — ¸m ' a A`  ¦ : Ÿ x K  F   & ñ  o õ & ñ _  ”  ' Ÿ   © œI \  ¦ S X ‰ “  

% i  . ] j Œ • ¢ - a « Ñ  ) a r « Ñ_  ³ ð€  “ É r Å Ò  „    ‰ & ³p  â (Field emission scanning electron microscopy: FESEM, JEOL JSM-7000F)`  ¦  6   x # Œ › ' a ¹ 1 Ï % i Ü ¼ 9, \  -t  ì  r í

ß –+ þ A ì  rF  g (Energy dispersive spectroscopy: EDS) ì  r$ 3 `  ¦ :

Ÿ

x K  ³ ð€  \  à ºf ”  ~ ½ ӆ ¾ ÓÜ ¼– Ð_  Al8 £ x õ  Si8 £ x _  & h 8 £ x í  H " f

\

 ¦ S X ‰ “   % i “ ¦, Ê ê~ ½ Ó „   í ß –ê ø Í r] X  (Electron backscatter diffraction: EBSD) ì  r$ 3 `  ¦ : Ÿ x K     & ñ Si   & ñ w n _  C 

†

¾ Ó$ í `  ¦ ¨ î Ù þ ¡ .

III. + s ÇÊ Ý õ m Í w Š²  o

Figure 2  H  © œ“ : r \ " f Û ¼( ' Z O Ü ¼– Ð glass l ó ø Í 0 A\  $ í



© œr †   ZnO ³ ð€  _  AFM s p t \  ¦
  · p  כ s  . ZnO _

 ³ ð€    } 9 l  (root mean square: RMS)  H Fig. 2(a):

0.73 nm, Fig. 2(b): 1.42 nm, Fig. 2(c): 2.4 nm % i  . ZnO _

 ³ ð€    } 9 l   H Û ¼( ' a A r _  O ² _  Ä »| ¾ Ó`  ¦ Fig. 2(a):

0 sccm ( C  â · ú š§ 4  : 3 × 10 ⁻³ torr) , Fig. 2(b): 8 sccm ( C  â · ú š§ 4  : 5 × 10 ⁻³ torr), Fig. 2(c): 10 sccm ( C  â · ú š

§ 4

 : 6 × 10 ⁻³ torr)`  ¦    o # Œ ] j# Q % i  . s „   ƒ  ½ ¨ _

   õ \ " f  H Û ¼( ' \  ¦ : Ÿ x ô  Ç ZnO $ í  © œ r  í ß –™ è / B N/ å L | ¾ Ó s

 7 £ x ½ + Éà º2 Ÿ ¤ r « Ñ ³ ð€   © œ_  { 9  _  s 1 l x • ¸ ² ú ˜ t 

“

¦ $ í  © œ r  ³ ð€  _  + þ AI   H { 9  ç ß –_  Ø  æ[  t   H \  -t    



o\  % ò † ¾ Ó`  ¦ ~ à Î  í ß –™ è / B N/ å L | ¾ Ós  7 £ x  ½ + É Ã º2 Ÿ ¤ ³ ð€     } 9

l  7 £ x ô  Ç  [12–16]. ‘ : r ƒ  ½ ¨\ " f• ¸ Û ¼( ' a A ×  æ C 

 â

· ú š§ 4 _  7 £ x \  _ K  ~ à Ì} Œ •_  ³ ð€  _   } 9 l  7 £ x  ô  Ç

 כ

Ü ¼– Ð ó ø Íé ß –  ) a  .

s

X O >  " f– Ð   É r ³ ð€    } 9 l \  ¦ t   H ZnO r 

«

Ñ\ , Al `  ¦ \ P 7 £ x ‚ Ã Ì Ê ê α-Si`  ¦ Û ¼( ' a A # Œ α- Si/Al/ZnO/glass _  ½ ¨› ¸\  ¦ ° ú   H r « Ñ\  ¦ ] j Œ • % i  . ‘ : r

Fig. 2. (Color online) Atomic force microscope images of the ZnO grown on a glass substrates : (a) ZnO/glass (ZnO RMS: 0.73 nm), (b) ZnO/glass (ZnO RMS: 1.43 nm), (c) ZnO/glass (ZnO RMS: 2.4 nm). The insets in the upper-right corner are the pictures of each sample.

ƒ

 ½ ¨\ " f  H Fig. 2 ü < ° ú  s  " f– Ð   É r ³ ð€    } 9 l \  ¦  t

  H ZnO \  ¦ s 6   x # Œ 3> h_  r « Ñ\  ¦ ï  r q  % i Ü ¼ 9, 8 £ x

“

§ ¨ 8 Š $ í  © œ`  ¦ : Ÿ x # Œ    & ñ Si `  ¦ $ í  © œ % i  . \ P % ƒo \  _

ô  Ç    & ñ Si + þ A$ í `  ¦ S X ‰ “   l  0 A # Œ \ P % ƒo  „  /Ê ê\  ¦ q

“ § % i  .

Figure 3“ É r \ P % ƒo \  ¦ : Ÿ x ô  Ç 8 £ x “ § ¨ 8 Š $ í  © œ`  ¦ S X ‰ “   l  0 A ô

 Ç SEM x 9  EDS B i ç s p t s  . Fig. 3(a)_  ¢ , aA á ¤ s p  t

  H \ P % ƒo  „   α-Si/Al/ZnO/glass _  & h 8 £ x ½ ¨› ¸\  ¦ ° ú   H

Fig. 3. (Color online) Cross-sectional SEM im- ages and EDS mapping of the sample; (a) as- deposited sample with a stacking sequence of amorphous- Si/Al/ZnO/glass, and (b) annealed sample at 577 ^◦ C for 3 hour which has a stacking sequence of Al/poly- Si/ZnO/glass.

r

¼ # _  é ß –€   SEM  ”   s  9, š ¸ É rA á ¤“ É r 1 l x{ 9  r « Ñ_  EDS B

i ç s p t \  ¦
  · p . EDS B i ç `  ¦ : Ÿ x K  y Œ •y Œ •_  8 £ x \  K

{ © œ   H Ó ü t| 9 `  ¦ ì  r$ 3  # Œ ³ ðr  % i  . Fig. 3(b)_  ¢ , aA á ¤ s

p t   H 577 ^◦ C _  “ : r • ¸\ " f \ P % ƒo  Ê ê + þ A$ í  ) a Al/    

&

ñ -Si/ZnO/glass _  & h 8 £ x ½ ¨› ¸\  ¦ ° ú   H r ¼ # _  é ß –€   SEM s

p t \  ¦
 ? / 9, š ¸ É rA á ¤“ É r 1 l x{ 9  r « Ñ_  EDS B i ç `  ¦ :

Ÿ

x # Œ Al 8 £ x õ  Si 8 £ x s  “ § ¨ 8 Š ÷ &# Q e ” 6 £ §`  ¦ S X ‰ “   % i  .

s

 Qô  Ç 8 £ x “ § ¨ 8 Š á Ԗ Ð[ jÛ ¼_  B j& m 7 £ §“ É r  6 £ § õ  ° ú  s  [ O 

"

î ½ + É Ã º e ”  . \ P % ƒo  õ & ñ ×  æ, Al ? / Җ Ð Si s  6   xÖ 6 x ÷ &# Q [

þ

t # Ql  r  Œ •   H X < Al _  › ¸$ í s   Œ •“ É r ZnO _  ³ ð€   Ò



 H \ " f  H ì ø Í@ /– Ð Si _  $ 3 Ø  ¦ s  { 9 # Qè ß – .   " f ZnO ³ ð

€

 \ " f  H Si _    & ñ w n  + þ A$ í s  r  Œ •÷ &# Q   & ñ  o s À Ò

#

Qt  9, s  Qô  Ç   & ñ w n `  ¦ ×  æd ” Ü ¼– Ð   & ñ $ í  © œs  ”  ' Ÿ ÷ &

#

Q    & ñ Si s  + þ A$ í  ) a   [17]. { 9 ì ø Í& h Ü ¼– Ð Si   & ñ w n  Ò q t

$ í

5 Å q • ¸  H $ í  © œ“ : r • ¸ü < Si _  6   x K 5 Å q • ¸ (6   x K e  ¦! 3 Û ¼) x 9  Si _  s 1 l x • ¸ 1 p x _  “   \  _ K  % ò † ¾ Ó`  ¦ ~ à ΍  H   [17]. ¢ ¸ ô

 Ç 1 l x{ 9  “ : r • ¸\ " f Si _  6   x K 5 Å q • ¸  H Al-Si _  › ¸$ í \  _ 

”

> r l  M :ë  H \  ZnO ³ ð€  _   } 9 l \  _ K  Al8 £ x õ  Si 8 £ x _

 > €   Â Ò   H \ " f ² D G  Ò& h “   › ¸$ í    o e ”   H  â Ä º\   H

Fig. 4. (Color online) Optical micrograph of the annealed samples at 577 ^◦ C for 0, 30, 40 min; (a) sample-A, (b) sample-B, and (c) sample-C. The black areas in the pic- ture correspond to the poly-Si grains.

6  

x K  e  ¦! 3 Û ¼• ¸    o # Œ Si   & ñ w n _  $ í  © œs  8 ú ¤”   ¢ ¸  H t

ƒ  ÷ &  H % ò % i s  µ 1 ÏÒ q t½ + É Ã º e ”  . s  Qô  Ç $ í  © œ5 Å q • ¸_  Ô  ¦ ç

 H+ þ A  © œI  5 Å q \ " f  H œ íl \  + þ A$ í  ) a   & ñ w n _  x 9 • ¸   



o €     õ & h Ü ¼– Ð    & ñ Si_  $ í  © œ5 Å q • ¸ ² ú ˜ | 9  à º e ”

 . ¢ ¸ô  Ç   & ñ w n `  ¦ ×  æd ” Ü ¼– Ð $ í  © œs  t 5 Å q ÷ &l  M :ë  H \  ZnO ³ ð€  _   } 9 l   H   & ñ w n _  ß ¼l ü < C † ¾ Ó~ ½ ӆ ¾ Ó\  % ò

†

¾ Ó`  ¦ ×  ¦ à º e ” “ ¦ Ò q ty Œ • ½ + É Ã º e ”  .

Figure 4  H ‘ : r ƒ  ½ ¨\ " f Si   & ñ w n  + þ A$ í õ & ñ `  ¦ ì  r$ 3 

l  0 AK  \ P % ƒo  ×  æ glass \  ¦ : Ÿ x K  › ' a ¹ 1 Ïô  Ç r « Ñ_  F  g † < Æ

‰

&

³p  â  ”  `  ¦
  · p . Fig. 4(a) ∼ (c)  H y Œ •y Œ •  } 9  l

 0.73 nm, 1.42 nm, 2.4 nm“   ZnO0 A\  Al `  ¦ \ P 7 £ x

‚ Ã

Ì Ê ê α-Si `  ¦ Û ¼( ' a A # Œ α-Si/Al/ZnO/glass_  ½ ¨› ¸

\

 ¦ ° ú   H r « Ñ\  ¦ ] j Œ • % i Ü ¼ 9, ZnO ³ ð€    } 9 l \     Sample-A (ZnO RMS : 0.73 nm), Sample-B (ZnO RMS : 1.42 nm), Sample-C (ZnO RMS : 2.4 nm) 3 > h_  r « Ñ

\

 ¦ ï  r q  % i  . — ¸Ž  H r « э  H 577 ^◦ C \ " f \ P % ƒo  % i  .



”  \ " f | 9 “ É r  rÒ  o  Òì  r“ É r F   & ñ s  ”  ' Ÿ ×  æ“   Si s  9,

ƒ

 ô  Ç  rÒ  o  Òì  r“ É r α-Si`  ¦
  · p .

\ P

% ƒo  „   (0 min) r « Ñ_  ³ ð€  \   H : £ ¤Z > ô  Ç + þ A © œs  › ' a

¹

1 Ï÷ &t  · ú §€ Œ ¤Ü ¼ 9, ZnO ³ ð€  _   } 9 l  7 £ x ½ + Éà º2 Ÿ ¤ 1 l x { 9

ô  Ç r ç ß – \ P % ƒo  ”  ' Ÿ ÷ &% 3 6 £ § \ • ¸ Ô  ¦ ½ ¨ “ ¦ œ íl \    

&

ñ w n _  x 9 • ¸ Z  }  t “ ¦   " f   & ñ  oÖ  ¦ s  7 £ x  “ ¦ e ” 



 H  כ `  ¦ S X ‰ “  ½ + É Ã º e ”  . s M :   & ñ w n _  x 9 • ¸  H ZnO _ 

} 9 l  & | 9 à º2 Ÿ ¤ 7 £ x  # Œ · ú ¡\ " f \ V © œô  Ç  ü < ° ú  s  ZnO ³ ð€  _   } 9 l  ² D G  Ò& h “   › ¸$ í _     o\  ¦  l  

#

Œ ² D G ™ è& h “     & ñ w n  + þ A$ í s  8 ú ¤”  ÷ &  H  כ Ü ¼– Ð ˜ Г   .

s

 Qô  Ç   õ   H   É r › ' a& h \ " f• ¸ [ O " î | ¨ c à º e ”   H X <, 



© œ ¨ î ò ø Íô  Ç ZnO 0 A\ " f F   & ñ  o ”  ' Ÿ  ) a r « э  H   É r r

« Ñü <  Ø Ô>  D ! p× ¼ s à Ô+ þ A   & ñ w n s  + þ A$ í ÷ &  H   õ 

Fig. 5. Annealing time dependency of crystallized frac- tion. The crystallization rate of poly-Si is closely related with the roughness of ZnO.

› '

a ¹ 1 Ï÷ &% 3 Ü ¼ 9 (Fig. 4(a)) s  Qô  Ç + þ A © œ“ É r $ í  © œ7 á x _  S X ‰ í ß –

o  Ø  æì  r y  |    © œI , 7 £ ¤ $ í  © œ5 Å q • ¸ Ø  æì  r y  Ö ¼ 2 ;  â Ä

º\  ŠҖ Ð › ' a ¹ 1 Ï÷ &  H   õ – Ð, · ú ¡\ " f [ O " î ô  Ç  כ õ  ° ú  s  Si õ

 Al _  > €  s  / å Lï  r ô  Ç  â Ä º (7 £ ¤, ¨ î ò ø Íô  Ç ZnO 0 A\  7 £ x ‚ à Ì

 )

a r « Ñ)  H › ¸$ í _  ì  r Ÿ í ç  H{ 9  # Œ q “ §& h    & ñ w n _  x 9 

•

¸ ± ú >  + þ A$ í s  ÷ &l  M :ë  H \  $ í  © œ7 á x _  S X ‰ í ß – o  U  ´

#

Q4 R" f
 
  H   õ – Ð K $ 3 ½ + É Ã º e ”  .

Figure 5  H 8 £ x “ § ¨ 8 Š $ í  © œ ×  æ, F  g † < Æ ‰ & ³p  â Ü ¼– Ð z  ´r ç ß –

› '

a ¹ 1 Ïô  Ç  ”  \ " f   & ñ  oÖ  ¦ _     o\  ¦ > í ß – # Œ & ñ o ô  Ç

 

õ s  . Fig. 5(c)  H ZnO  } 9 l   © œ  H Sample- C s  9, 40ì  r ë ß –\    & ñ  o ¢ - a « Ñ (  & ñ  oÖ  ¦ ∼84%) ) a ì ø

̀  , Fig. 5(b), (a)ü < ° ú  s  q “ §& h  B ã ¼ Qî  r ³ ð€  `  ¦

”   Sample-B\ " f   & ñ  o  H 70ì  r (  & ñ  oÖ  ¦ ∼65%), Sample-A \ " f  H 120ì  r (  & ñ  oÖ  ¦ ∼62%) \  ¢ - a « Ñ÷ &% 3 



. ZnO  } 9 l   © œ  H r « Ñ\ " f Si   & ñ  oÖ  ¦ s   © œ À

1 Ï| à ÛÜ ¼ 9, s   H F   & ñ  o_  ”  ' Ÿ  & ñ • ¸  } 9 l _  7 £ x 

\

    7 £ x † < Ê`  ¦ _ p ô  Ç . s  Qô  Ç   õ   H · ú ¡" f Fig. 4\ 

"

f• ¸ [ O " î % i 1 p w ZnO _   } 9 l  7 £ x † < Ê\       & ñ w n  _

 x 9 • ¸ 7 £ x  % i l  M :ë  H \  $ í  © œ7 á x _  S X ‰ í ß – o   ú ª



4 R   & ñ  o_  ”  ' Ÿ 5 Å q • ¸ À 1 Ï t   H ´ òõ \  ¦ 4 Rš ¸“ ¦ e ”  6

£

§`  ¦
  · p . ¢ ¸ô  Ç Fig. 4(b)ü < (c) \ " f  H q “ §& h  " é ¶+ þ A

\

  î  r   & ñ w n s  % 3 # Q& ’ l  M :ë  H \    & ñ w n _  ¨ î ç  Hf ” 

 â

`  ¦ Ò q ty Œ •K  ^  ¦ à º e ” % 3   H X <, Fig. 4(c)_   â Ä º ¨ î ç  Hf ”  â s

 ∼20 µm – Ð 7 á x A _  ƒ  ½ ¨  õ \  q “ §K " f  H   & ñ w n  s

 + þ A$ í ÷ &  H  כ `  ¦ S X ‰ “  ½ + É Ã º e ” % 3  .

Figure 6“ É r ZnO ³ ð€    } 9 l _     o\    É r Si _  C 

†

¾ Ó ~ ½ ӆ ¾ Ó`  ¦ › ¸  l  0 A # Œ ”  ' Ÿ ô  Ç EBSD ì  r$ 3   õ s 



.  ”  \ " f  Ž “ É r  Òì  r“ É r α-Si s  9 Ò  o © œ\     Si _ 

 

& ñ €   ~ ½ ӆ ¾ Ó`  ¦ S X ‰ “  ½ + É Ã º e ”  . ¢ ¸ô  Ç,  Ž “ É r  Òì  r _  €  & h 

Fig. 6. (Color online) In-plane EBSD images of the sam- ples; (a) sample-A, (b) sample-B, and (c) sample-C. One can observe that the preferential orientation of the poly- Si is closely related with the roughness of ZnO.

“

É r ZnO _  ³ ð€    } 9 l  7 £ x  ½ + Éà º2 Ÿ ¤ y Œ ™™ è % i Ü ¼ 9, s 



 H Fig. 4 _    õ ü < 1 l x{ 9 ô  Ç   õ \  ¦
 ? /“ ¦ e ”  . ‘ : r ƒ  

½

¨\ " f  H · ú ¡" f [ O " î ô  Ç  ü < ° ú  s  Sample-A \ " f (100) C

† ¾ ÓÒ  ¦ s  €  • 17% s  9 Sample-B  H (100) C † ¾ ÓÒ  ¦ s  €  • 31% s “ ¦ sample-C_   â Ä º (100) C † ¾ ÓÒ  ¦ s  €  • 51% s  © œ s

 › ' a ¹ 1 Ï÷ &% 3  . s „   ƒ  ½ ¨   õ _   â Ä º (100) ~ ½ ӆ ¾ ÓÜ ¼– Ð _

 C † ¾ ÓÒ  ¦ s  €  • 60%s  9   & ñ w n _  ¨ î ç  Hf ”  â s  €  • 5 µm

&

ñ • ¸ e ” `  ¦ [18] “ ¦ 9 €   ³ ð€  s   • 2 ; ZnO \  ¦ s 6   x ô  Ç  â Ä

º  H   & ñ w n õ  q “ §& h  Z  }“ É r C † ¾ ÓÖ  ¦`  ¦ ° ú   H X < Ä »o † < Ê`  ¦

· ú

˜ à º e ”  .

#

Œl " f (100) C † ¾ Ós  % 3 # Q”   s Ä »\  @ /K " f “ ¦¹ 1 Ͻ + É € 9  כ

¹ e ”  . G. Willeke 1 p x“ É r [9] Si   & ñ + þ A$ í r    & ñ €  Z > 

$ í

 © œ5 Å q • ¸\  @ /ô  Ç ƒ  ½ ¨   õ \  ¦ [ O " î   H ç ß –é ß –ô  Ç — ¸4 S q`  ¦ ]

jr  % i  . Si (100) €  “ É r q “ §& h  Z  }“ É r ³ ð€   \  -t \  ¦ ° ú 



 H ì ø ̀  , Si (111) €  “ É r  © œ ± ú “ É r ³ ð€   \  -t \  ¦ ° ú   H  .



 " f, $ í  © œ5 Å q • ¸  H  â Ä º\   H Si (100)   & ñ €  s  % 3 # Q t

l  / 'Ä º 9, $ í  © œ5 Å q • ¸ Ø  æì  r y  Ö ¼ 9t €   Si(111)   & ñ

€

 s  % 3 # Qt l  ~ 1    H  כ s  . ‘ : r ƒ  ½ ¨_   â Ä º\   H { 9 ì ø Í

&

h “    â Ä º˜ Ð • ¸ $ í  © œ5 Å q • ¸ À 1 Ï| à ÛÜ ¼ 9 s – Ð “   # Œ Z  }

“

É r (100)   & ñ €  `  ¦ ° ú   H    & ñ Sis  % 3 # Q”    כ Ü ¼– Ð ó ø Íé ß –

 ) a  .

IV. + s Ç Â ] Ø

‘

: r ƒ  ½ ¨  H ZnO ~ à Ì} Œ •0 A\  Al-Si 8 £ x “ § ¨ 8 Š $ í  © œZ O `  ¦ : Ÿ x ô  Ç



  & ñ Si_  $ í  © œr  ZnO ³ ð€  _   } 9 l  Si   & ñ $ í \ 

p

u   H % ò † ¾ Ó\  @ / # Œ › ¸  % i  . Õ ª   õ  8 £ x “ § ¨ 8 Š $ í  © œ

`

 ¦ : Ÿ x ô  Ç    & ñ Si_  $ í  © œ5 Å q • ¸ü <   & ñ w n _  ß ¼l  x 9  C 

†

¾ Ó$ í s  ZnO_  ³ ð€    } 9 l ü < x 9 ] X  >  › ' aº   e ”   H  כ Ü ¼

–

Ð
 z Œ ¤Ü ¼ 9, ZnO ³ ð€    } 9 l  7 £ x  ½ + Éà º2 Ÿ ¤ Si   & ñ w n

 + þ A$ í 5 Å q • ¸ 7 £ x  % i “ ¦,   & ñ _  f ”  â s  7 £ x  % i Ü ¼ 9 (100) C † ¾ Ó$ í `  ¦ ° ú   H     & ñ Sis  + þ A$ í ÷ &  H  כ `  ¦ · ú ˜ Ã

º e ” % 3  .   " f ~ à Ì} Œ •+ þ A I € ª œ„  t  ] j Œ •`  ¦ 0 Aô  Ç    & ñ Si ~ à Ì} Œ • + þ A$ í r  Z > • ¸_  „  F G+ þ A$ í / B N& ñ s  € 9 כ ¹ \ O s  ZnO

\

 ¦ s 6   x # Œ   É r F   & ñ  oü <  H   & ñ w n `  ¦ ° ú   H    & ñ Si s  6   x s  >  ½ ¨‰ & ³½ + É Ã º e ”    H  כ `  ¦ · ú ˜ à º e ” % 3  .

P

c p 8 ý ò k >

‘

: r ƒ  ½ ¨  H p A ‚ ½ ӛ ¸õ † < ÆÂ Ò x 9  & ñ ˜ Ð: Ÿ x’  í ß –\ O ”  < É ª" é ¶ _ 

@

/† < Æ ITƒ  ½ ¨G ' p'  ¹ ¢ ¤$ í t " é ¶  \ O _  ƒ  ½ ¨  õ – Ð Ã º' Ÿ ÷ &

% 3

6 £ § (NIPA-2013-H0301-13-2009). ¢ ¸ô  Ç, 2012¸  • ¸ @ /ô  Ç



 ² D G & ñ Â Ò (“ §¹ ¢ ¤ õ † < Æl Õ ü t  Ò)_  F " é ¶ Ü ¼– Ð r ' Ÿ    H ô  Dz D G

ƒ

 ½ ¨F é ß – ² D G ] ja ž ?§ 4  \ O _  t " é ¶ Ü ¼– Ð Ã º' Ÿ   ) a ƒ  ½ ¨  õ e ”  ( õ ] j    ñ: D00013).

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