Growth of p-Zn
0.31Cd
0.69Se Thin Films by Using a Vacuum Evaporation Method and Their Physical Properties
Dong Hun Han · Eun Jeong Yoon · Jeoung Ju Lee∗
Department of Physics and Research Institute of Natural Science, Gyeongsang National University, Jinju 660-701, Korea
Kwang Yong Kang
Convergence of IT Devices Institute, Dong-Eui University, Busan 614-714, Korea (Received 24 October 2014 : revised 26 November 2014 : accepted 1 December 2014)
Zn0.31Cd0.69Se films were prepared on indium-tin-oxide(ITO)-coated glass substrates by using thermal evaporation. X-ray diffraction spectra showed that the Zn0.31Cd0.69Se films had a mixed ZnSe and CdSe zincblende structure with a lattice constant a = 6.077 ˚A and that the crystals were preferentially grown with a (111) orientation. The optical energy band gap, measured at room temperature, of the as-deposited Zn0.31Cd0.69Se film was 2.05 eV and decreased to about 2.04 eV
∼ 1.96 eV upon annealing in a vacuum electric furnace at temperatures from 200◦C to 500◦C.
The dynamical behavior of the charge carriers in the Zn0.31Cd0.69Se film was investigated by using photoinduced discharge characteristics (PIDC) techniques.
PACS numbers: 81.15.-z, 81.05.Hd
Keywords: Zn0.31Cd0.69Se thin film, Annealing effect, Energy band gap, Surface roughness, PIDC
à Ã
Å « Ö «Y c l0 n É; c 8 ý X ¢ p-Zn
0.31Cd
0.69Se U c lT c l8 ý V R ËX ê s õ m Í ° Ç% iP Æ X Øy ¢; c  \ ¥ ö
n ÚP X ì Ä V R Ëù m Ç
Â6
Òò6BgY@ · *×<ª<+ä · T+䮣∗
â
©@/<Ƨ õ<Æ@/<Æ Óüto<Æõ x9 líõ<ƽ¨è, ÅÒ 660-701
~ç
¡¢9÷7B
1 l
x_@/<Ƨ ÂÒíßITÖ6x½+ËÂÒ¾¡§½¨è, ÂÒíß 614-714
(2014¸ 10Z4 24{9 ~ÃÎ6£§, 2014¸ 11Z4 26{9 ú&ñ:r~ÃÎ6£§, 2014¸ 12Z4 1{9 >FSX&ñ)
/BN7£xÃÌ ZOܼРITO (indium-tin-oxide) lóøÍ 0A\ Zn0.31Cd0.69Se~ÃÌ}`¦]j %i. X- r]X ì
r$3\ _ # ~ÃÌ}_ ¶ú½Ó©ÃºH a = 6.077 ˚AܼРZnSeü< CdSe_ $3F g ½¨¸\¦ ¦ e%3ܼ 9, Õª $í©~½Ó¾ÓÉr (111)~½Ó¾ÓܼРĺ $í©Hd`¦ ·ú ú e%3. 7£xÃÌ)aZn0.31Cd0.69Se~ÃÌ}\ @/
#
z´:r\"f 8£¤&ñôÇF g<Æ&h \ -t { çß Ér 2.05 eVs%3¦, \P%o :r¸\¦ 7£x<Ê\ yè
%iܼ 9, 200◦C ∼ 500◦CÐ \P%oôÇ ~ÃÌ}_F g<Æ&h \ -t { çß Ér 2.04 eV ∼ 1.96 eVs%3.
Zn0.31Cd0.69Se~ÃÌ} ?/_ î rìøÍ[þt_ 1lx%i<Æ&h 1lx`¦F gÄ»l ~½Ó :£¤$í (PIDC: photoinduced discharge characteristics)~½ÓZOܼР¸ %i.
27
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
PACS numbers: 81.15.-z, 81.05.Hd
Keywords: Zn0.31Cd0.69Se~ÃÌ}, \P%o ´òõ, \ -t { çß , ³ð }9l,F gÄ»l ~½Ó :£¤$í
I. "e Â]Ø
II-VI7á¤_ "é¶è[þtÉr { çß s V,Ér (wide band gap) F
gè[þt`¦]j½+É Ãº eHF§4 M:ëH\ ß¼> ÅÒ3lq
~ Ã
Φ e [1–3]. :£¤y IªF g_ r%ò%i\"f Z}Ér f¨ Ã
º>ú, ¦´òÖ¦_ 4¤F ½+Ë Õªo¦ { çß [þt`¦·ú´ú
>
¸]X½+É Ãº eH :£¤fç M:ëH\ II-VI7ᤠìø͸^[þts Ö¸ µ
1Ï > ½¨÷&¦ e [4]. a-e7ᤠo½+ËÓüt ìø͸^[þt MX[ab7ᤠFK5Åq (metal): M=Zn, Cd, Hgü< ea7᤺úïp (chalcogen): X=S, Se, Te]H½¨¸&h :£¤$í÷ rëß m, l
x9 F g<Æ&h :£¤$í M:ëH\F g#30A > ½¨÷&#QM®o [5, 6]. MX_ CdSeH z´:rõ @/l·ú \"f ¹¢¤~½Ó, ĺØÔs à
Ô (hexagonal, wurtzite) [/BNçßçH:P63mc(C6v4 )]½¨¸Ð
&
ño÷& 9, ï rîß&ñ ©I (metastable state)s &ñ¹¢¤^,
$
3F g(cubic, zincblende) [/BNçßçH:F¯43m(Td2)]½¨¸Ð
&ño|¨c ú e [7]. ZnSeH ^, $3F g (tetra- hedral, zincblende) [/BNçßçH:F¯43m(Td2)]½¨¸Ð"f d &ñ
¹
¢¤^ (FCC: face centered cubic) &ñ½¨¸\¦ ¿º "é¶
\¦"fÐ ½+Ër ½¨¸Ð &ño|¨cú e [8,9]. CdSe (Eg= 1.9 eV)HF glo<Æ t (photoelectro-chemical cells)ü<F g¸ t (photoconductive cells)_ f¨Ãº8£xܼ
Ð 6 x|¨cú eHìøÍ, ZnSe (Eg= 2.7 eV)HV,Ér{ çß
M:ëH\ ÀÒpW1G'pÛ¼ (luminescent) x9 µ1ÏF g(light emit- ting)è Õªo¦ ¦´òÖ¦ òøÍ r Iªt ¨8l (high- effective tandem solar converters)_ ½Ó (window)ܼР6
x|¨c ú e. Õª Q CdSe F glo<Æ tÐ 6 x
÷
&%3`¦M:F gÂÒd (photo-corrosion)s µ1ÏÒqt HX< ìøÍK, ZnSeHV,Ér{ çß M:ëH\F g Ö¸$í (photo-active)Ér _
\O tëß 8 îß&ñ H כ s ·ú 94R e [10,11]. ¸ Z
þ
t±ú_ ½¨ ÆÒ[jH a-e7á¤s"é¶o½+ËÓüt\ a7ᤢ¸H e 7
ᤠ"é¶è\¦' ¦ o<Æ|¾Ó:r¸$íq (stoichiometric ra- tio)\¦¸]X # "é¶o½+ËÓüt`¦½¨$íôÇ Êê ìø͸^_ :£¤$í
`
¦>h ¦ H½¨\¦Ö¸µ1Ïy 'K ¸¦ e [12, 13]. CdSeü< ZnSe o½+ËÓüts ½+Ë # Zn`¦lìøÍܼÐ
H a-e7ᤠ"é¶o½+ËÓüts |¨cM:, ¿º o½+ËÓüt_ ©&h`¦t m
H ZnCdSe"é¶o½+ËÓüt`¦]j½+É Ãº e. o½+ËÓüt_ ¸
$í
q\ \ -t { çß s Érìø͸^F«Ñ\¦]j/BN
> ÷& 9, IªF g_ f¨Ãº\¦ 7£xrv¦ 1lxr\F gÂÒd
`
¦}H%i½+É`¦½+É Ãº e [12,14]. þjH\H a-e7á¤o
½
+ËÓütìø͸^ ÷ rëß m @/ÂÒì r_ ìø͸^ lìøÍ è >h
∗E-mail: [email protected]
µ
1Ï â¾ÓÉr¦, Z>¦, ·ûªÜ¼"f $í0pxs ĺúôÇ è\¦ ]
j 9HÆÒ[j\ ~ÃÌ}\ @/ôÇ 'ads &t¦ e
. "f a-e7ᤠo½+ËÓüt ìø͸^ ~ÃÌ}Ér ì r¶ú \x
×þ
r (molecular beam epitaxy, MBE) [13,15], "é¶s1lx 7
£
x \x×þr (migration enhanced epitaxy, MEE) [16], ì
rÁº \Pì rK ~½ÓZO (spray pyrolysis method) [17], Ä»lFK 5
Å
q o<Æ l©7£xÃÌ (metal organic chemical vapor depo- sition, MOCVD) [18], l7£xÃÌ (electrodeposition) [19], Ä
»lFK5Åql© \x×þr (metal organic vapor phase epi- taxy, MOVPE) [20], `OÛ¼ ¸FKlÕüt (pulse plating tech- nique) [12], /BN7£xÃÌ(vacuum evaporation) [6], `OÛ¼ YU s
$ 7£xÃÌ (pulsed laser deposition, PLD) [21], ۼ߼2;
W (screen printing) [22], o<Æ6 xl7£xÃÌ (chemical bath deposition, CBD) [23] 1px_ ªôÇ lÕütÐ ]j÷&#Q M®o
.
"f a-e7ᤠ"é¶o½+ËÓüt ìø͸^ ]j ~½ÓZO_ èH Â
Ò µ1Ï\ _K ZnxCd1−xSe \x8£x (epilayers)õ ZnxCd1−xSe/ZnSe s7áx]X½+˽¨¸ (heterostructures) 8
£
x~ÃÌ}_ $í©¸ 0px > ÷&%3. sü< °ú s ªôÇ \ x
8£xõ 8£x~ÃÌ} ]j ~½ÓZO_ >hµ1ÏÐ K ½¨¸&hܼРî
ß&ñ 9, l&h, F g<Æ&hܼР:£¤$ís 8A#Qèß "é¶o½+Ë Ó
ü
t ~ÃÌ}`¦ ]j ¦ e [24]. Li 1px [18]Ér Ä»lFK5Åq
o<Æ l©7£xÃÌ ZO\ _K"f $í©)a ZnSe/ZnxCd1−xSe
í (superlattices)ÐÂÒ' ×æí7H ëßíßêøÍ (mul- tiphonon Raman scattering)`¦ ¸ # ©#48£x (bar- rier layers)\"f ¿º 7áxÀÓ_ ZnSe-like [jÐF g<Æ (longi- tudinal optical) í7H`¦ SX %i. Tamargo 1px [16]Ér InP lóøÍ 0A\ ZnCdSe/ZnCdMgSe_ ªÄºÓüt (quan- tum well, QW) ½¨¸\¦ $í© # µ1ÏF g s¸×¼\¦ ]j
%i¦, F g<Æ&h :£¤$í¸ ¸ %i. Guan 1px [25]õ Shubina 1px [26]Ér ì r¶ú \x×þr\ _K"f $í©)a ZnxCd1−xSe/ZnSeí ÐÂÒ' íÐÀÒpW1G'pÛ¼ (pho- toluminescence, PL)\¦¸ # F g<Æ&h ©îß&ñ$í_ l
"
é
¶`¦µ1ß+ÀI¦, Liu 1px [27]Ér CdZnS/ZnS core/shellª&h (quantum dot, QD)`¦ ]j # :£¤$í`¦ ¸ %iܼ 9,
¢
¸ôÇ ª&hs ªÄºÓüts F gíßo (photo-oxidation)
6 x,¨8 â x9 o<Æ&h o\ y©ôÇ íÐÀÒpW1G'pÛ¼ è
Ð"f_ 6£x6 x$í¸ ½¨ %i [28]. s QôÇ ½¨[þtÉr Z}
É
r[Ouq6 xõ 7£xÃÌ 5Åq¸ Ö¼2; ©q\¦6 x %i.
Õ
ª Q :r ½¨\"fH 0A\"f /åLôÇ # Q t ~½Ó ZO
[þt ×æ\"f @/ &h 7£xÃÌs 0px 9 o<Æ|¾Ó:r¸$íq _
]j#Q 0px½+É ÷ rëß m, [Ouq6 xs q§&h &h
