Structural, Optical and Electrical Properties of CdO:Li Films Deposited by Using Spray Pyrolysis
Eun Yeong Shin · Dong Ju Seo ∗
Department of Physics Education, Chosun University, Gwangju 501-759, Korea (Received 7 July 2014 : revised 23 July 2014 : accepted 23 July 2014)
CdO:Li films were deposited on glass substrates by using spray pyrolysis. The 0.02 mol precursor solution was obtained by varying the concentrations of cadmium acetate and lithium chloride in twice-distilled water and was then sprayed on a heated glass substrate. The structural, optical and electrical properties of the CdO:Li films were studied using X-ray diffractometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, UV-VIS-NIR spectrophotometry and Hall-effect experiments. The CdO:Li films prepared with Li concentrations up to 10.0 at.% were identified as Li- doped CdO(CdO:Li) with (111) and (200) preferred orientations and a cubic structure. The optical transmissions of the CdO:Li films were about 60 ∼ 80% in the wavelength range from 500 nm to 900 nm and decreased with increasing Li concentration. The optical energy band gaps of the CdO:Li films increased with increasing Li concentration. The electric resistivity, carrier concentration, mobility and Hall coefficient of the p-type CdO:Li films deposited with a Li concentration of 8.0 at.%
were 1.3933 × 10
−4Ω·cm, 63.632 × 10
20cm
−3, 19.811 cm
2/V·s, and 0.0010 cm
2/C, respectively.
PACS numbers: 73.20.-r, 74.25.Gz
Keywords: CdO:Li films, Spray pyrolysis, Crystal structure, Optical transmission, Optical and electrical properties
Ä
Z Ø ¤° Ç Ä Z ØA 00 n É® z º V R ËX ê sc Ü R CdO:Li U c lT c l8 ý ºÑ ÷ ° Ë Ñ] K ¡X ì Ä, ¹ ÅM X ì Ä ¤V R Ë
,
>
ª <* å · " k ò 6 B® £ ∗
¸ @ / < Æ § Ó ü t o §¹ ¢ ¤ õ , F g Å Ò 501-759
(2014¸ 7 Z 4 7{ 9 ~ Ã Î6 £ §, 2014¸ 7 Z 4 23{ 9 Ã º& ñ : r ~ Ã Î6 £ §, 2014¸ 7 Z 4 23{ 9 > F S X & ñ )
CdO:Li ~ Ã Ì} ` ¦ ì r Á º\ P ì r K Z O Ü ¼ Ð Ä »o l ó ø Í 0 A\ $ í © r ( . CdO:Li ~ Ã Ì} ` ¦ $ í © r v l 0 AK 6
x ô Ç r É r Cadmium acetate, Lithium chloride, s 7 £ x À ÓÃ ºs 9, 0.02 mole ì r Á º6 xÓ o` ¦ ë ß [ þ t # Q
\ P ) a Ä »o l ó ø Í 0 A\ ì r Á º % i . $ í © ) a CdO:Li ~ Ã Ì} _ & ñ ½ ¨ ¸, F g < Æ& h : £ ¤$ í õ l & h : £ ¤$ í ` ¦ X- r] X ì rF g l , Å Ò & ³p â , \ -t ì r í ß " l oÛ ¼ ì rF g l , UV-VIS-NIR ì rF g l , Hall ´ òõ © u
\ ¦ s 6 x # ½ ¨ % i . CdO:Li ~ à Ì} _ & ñ ½ ¨ ¸ H (111), (200) s Ì º§  > $ í © ) a { 9 ~ ½ Ó½ ¨ ¸ s
9, Lis Ô ¦í HÓ ü t Ð ' ) a CdO(CdO:Li) ~ à Ì} Ü ¼ Ð S X ÷ &% 3 . CdO:Li ~ à Ì} _ F g È Òõ Ö ¦ É r 500 ∼ 900 nm % ò % i \ " f 60 ∼ 80%s % 3 ¦, Li_ 0 l x ¸ 7 £ x < Ê\ y è % i . CdO:Li ~ à Ì} _ F g < Æ
&
h \ -t ç ß É r Li 0 l x ¸ 7 £ x < Ê\ 7 £ x % i . Li` ¦ 8.0 at.% ' # $ í © r r « Ñ_ â Ä
º p-+ þ A ¸$ í s © a % ~ ¤Ü ¼ 9, q $ ½ Ó, î r ì ø Í 0 l x ¸, f . Ë > à º, s 1 l x ¸ H y y 1.3933 × 10
−4Ω·cm, 63.632 × 10
20cm
−3, 19.811 cm
2/V·s, 0.0010 cm
2/C s % 3 .
883
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PACS numbers: 73.20.-r, 74.25.Gz
Keywords: CdO:Li ~ Ã Ì} , ì r Á º\ P ì r K Z O , & ñ ½ ¨ ¸, F g È Òõ Ö ¦, F g < Æ& h l & h : £ ¤$ í
I. " e  ] Ø
CdO (Cadmium Oxide) H È Ò" î ô Ç ¸$ í í ß oÓ ü t (Transparent Conducting Oxides; TCO) Ð+ & ñ ½ ¨ ¸
H { 9 ~ ½ Ó½ ¨ ¸s 9, Cd ç ß < Êõ í ß è / B N ü < ° ú
É
r Å Ò> h < Ê_ II-IV ì ø Í ¸^ s . ¢ ¸ô Ç CdO ~ Ã Ì} É r r
F g % ò % i \ " f F g È Òõ Ö ¦ s Z } ¦ l & h ¸$ í s a % ~
É r n-+ þ A ~ Ã Ì} s [1]. CdO ~ Ã Ì} É r z ´ : r \ " f 2.2 ∼ 2.8 eV _ F g < Æ& h \ -t { ç ß ` ¦ ° ú H f ] X s + þ A ì ø Í ¸^ s
9, F g l & h : £ ¤$ í s a % ~ " f þ j H \ È Ò" î ô Ç F G, I
ª t , F g à Ô ½ t Û ¼' (photo-transistor), F g s ¸× ¼,
Û ¼G ' p" f 1 p x \ ´ ú §s s 6 x ÷ & ¦ e [2–5]. s Qô Ç 6 £ x6 x$ í M
:ë H \ È Ò" î ô Ç ¸$ í í ß oÓ ü t s F g è 1 p x \ ´ ú §s s 6
x ÷ & ¦ e Ü ¼ 9, F g è [ þ t _ ´ òÖ ¦ õ $ í 0 p x É r TCO Ó ü t| 9 _
l & h , F g < Æ& h : £ ¤$ í \ _ > r ô Ç . TCO Ó ü t| 9 _ l
&
h : £ ¤$ í ` ¦ > h l 0 A # r « Ñ\ Ô ¦í HÓ ü t` ¦ Å Ò{ 9
#
r « Ñ_ î r ì ø Í 0 l x ¸\ ¦ 7 £ x r v s 1 l x ¸\ ¦ 7 £ x r
& " f TCO Ó ü t| 9 _ l ¸ ¸\ ¦ ¾ Ó © r ~ ´ Ã º e Ü ¼ 9, r
« Ñ_ F g < Æ& h È Òõ Ö ¦ É r î r ì ø Í 0 l x ¸\ _ > r < Ês · ú 9 4
R e [6]. ¢ ¸ô Ç CdO ~ Ã Ì} _ : £ ¤$ í É r r « Ñ_ í ß o © I ü
< Ô ¦í HÓ ü t Ð ' ) a Ó ü t| 9 (Ti, F, In, Cr 1 p x) _ ª õ " é ¶ è
\
_ > r ¦, ~ Ã Ì} $ í © ¸| (l ó ø Í : r ¸, ì r Á ºÖ ¦, $ í © : r
¸, Ê ê\ P % o 1 p x) õ ~ Ã Ì} $ í © Z O 1 p x _ ¸| \ $ í ©
)
a ~ Ã Ì} _ Ó ü t o & h : £ ¤$ í s ² ú ¦ · ú 94 R e [1, 7,8].
TCO ~ à Ì} ` ¦ ] j ¸ H ~ ½ ÓZ O \ H / B N7 £ x à ÌZ O [9–11], RF-sputteringZ O [12–14], Chemical Bath Deposition (CBD) õ ì r Á º\ P ì r K Z O õ ° ú É r o < Æ& h ~ ½ ÓZ O [15–24] 1 p x s
s 6 x ÷ & ¦ e . / B N7 £ x à ÌZ O s RF-sputteringZ O 1 p x
É
r o < Æ& h ¸$ í ` ¦ ¸] X H כ É r Ä ºÃ º , ¦_ / B N
© u \ ¦ 9 כ ¹ Ð 9 ~ Ã Ì} _ $ í © 5 Å q ¸ Ö ¼o H é ß & h s
e . Õ ª Q ì r Á º\ P ì r K Z O É r ¦6 x ^ 6 xÓ o` ¦ \ P ) a l
ó ø Í 0 A\ ì r Á º # ì ø Í ¸^ ~ Ã Ì} x 9 S ! oÓ ü t ~ Ã Ì} ` ¦ $ í © r
v H ~ ½ ÓZ O Ü ¼ Ð" f ~ Ã Ì} ] j ¸ õ & ñ s É r ~ ½ ÓZ O \ q
#
ç ß é ß K © 6 x _ ¸$ í ~ Ã Ì} ] j ¸ 1 p x \ ´ ú §s s 6 x ÷ & ¦ e
. ¢ ¸ô Ç ì r Á º\ P ì r K Z O É r 6 xÓ o_ ¸$ í ` ¦ Ä »\ v > ¸
&
ñ < ÊÜ ¼ Ð+ o < Æ& h ¸$ í s { 9 & ñ ô Ç D ¥ ½ + ËÓ ü t` ¦ ì r Á º½ + É Ã º e
¦ l ó ø Í_ ß ¼l ¸ ª \ ] jô Ç` ¦ ~ Ã Ît · ú § H H © & h s
e .
´ ú
§ É r ½ ¨ [ þ t É r Ce, Ti, Al, Sn, In, F 1 p x` ¦ Ô ¦í HÓ ü t Ð '
ô Ç CdO ~ Ã Ì} ` ¦ $ í © r & ½ ¨ ¸& h , F g < Æ& h , l & h : £ ¤
∗
