Synthesized by Using the Combustion Method at Various Annealing Temperatures

Structural and Optical Characterizations of Al

O

:Eu

Synthesized by Using the Combustion Method at Various Annealing Temperatures

Sang-Min Park · Sayong Hong^∗

Department of Physics, Kongju National University, Gongju 314-701, Korea (Received 26 June 2013 : revised 20 August 2013 : accepted 12 November 2013)

Al2O3:Eu³⁺with a trivalent europium impurity of 0.5% mole ratio was synthesized by using the combustion method and was annealed at temperatures from 500 ^◦C to 1400 ^◦C in intervals of 100

◦C. The annealed samples showed the α-Al2O3:Eu³⁺ crystal phase in the X-ray diffraction data.

Photoluminescence experiments were carried out to determine the effects of annealing on Eu³⁺. The symmetry factor of the Eu2O3 cubic structure showed that the photoluminescence was influenced by the annealing temperature when Eu atoms, as impurities, were included in the Al2O3 matrix.

PACS numbers: 78.55.HX

Keywords: Combustion, Al2O3, Europium, Photoluminescence

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Al2O3:Eu³⁺ &ñ ?/\ Ä»–о¢§ (Eu³⁺) 0.5% ]tq_ Ô¦íHÓüts ÷&•¸2Ÿ¤ ƒ™èZOܼ–Ð Al2O3:Eu³⁺: Eu2O3`¦]j›¸ %i. Õªo“¦ 500 <sup>◦</sup>CÂÒ' 1400 <sup>◦</sup>Ct 100 <sup>◦</sup>Cçߖܼ–Ð #Qu´aA (annealing)`¦ 

%

i. #Qu´aA)a r«Ñ\ @/K "loÛ¼‚r]X Áº](\¦ 8£¤&ñ #Œ α-Al2O3:Eu³⁺ &ñ©œ`¦ ›'a¹1Ï %i“¦, Ÿí

ž

ÐÀÒpW1‚Û¼ 8£¤&ñZO\ _ôÇ #Qu´aA ´òõ\¦ z´+«> %i. Eu2O3 {9~½Ó½¨›¸_ @/gA“ (symmetry factor)H Ä»–о¢§ "é¶ Ô¦íHÓüt–Ð Al2O3 lìøÍ (matrix)\ Ÿí†<Ê÷&#Q4R e”`¦ M: #Qu´aA “:r•¸\ 

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†¾Ó`¦~Ã΍Hכ ܼ–Ð
zŒ¤.

PACS numbers: 78.55.HX

Keywords: ƒ™èZO, íߖo·ú˜ÀÒp³ou,Ä»–о¢§,ŸížÐÀÒpW1‚Û¼

I. "e Â]Ø

Al₂O₃“Ér ½™×¼Ì“ss @/|ÄÌ 9.4 eV [1] &ñ•¸–Ð Z}l M:ëH

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 y©œÄ»„^‰–Ð ´ú§s 6 x “¦ e”H Óüt|9–Ð+‹ Z}“Ér?/

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¸$íõ \P\ y©œôÇ :£¤$ís e”. ÕªQ
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∗E-mail: [email protected]

l 0AK"f 2072 ^◦C Ö6x&ht Z}#Œ l M:ëH\ ´ú§

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rq6 xõ 4Ÿ¤¸úšôÇ õ&ñs כ¹½¨)a. Õªo“¦ Ä»–о¢§ (Eu)

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é

¶H ß¼l M:ëH\ “¦“:r\"f ]j›¸½+É âĺ α-Al2O3 

&

ñ ?/\"f Ô¦íHÓüt–Ð ½+Ë÷&l #Q§>l M:ëH\ [2], â ]

j&h“ ~½ÓZOܼ–Ð Al²O3:Eu\¦ a%¦0qZO (sol-gel method)ZO [3]¢¸HÛ¼áÔYUs \PìrKZO (spray pyrolysis) [4] ܼ–Ð ]j 1207

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.

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:ëH\ Dh–Ðîr@/îߖܼ–Ð ƒ™èZO (combustion method)`¦ s

6 x #Œ çߖ¼# > Al²O3r«Ñ\¦ëߖ[þt#Q "é¶ H Ô¦íHÓüt

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¦•¸iç½+É Ãº e”H~½ÓZO\ @/K ƒ½¨ sÀÒ#Qt“¦ e” [5,6]. ƒ™èZOܼ–Ð Al2O₃:Eu³⁺`¦]j›¸½+É âĺ íH•¸ Z}“Ér é

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¸içôÇ ~½Ó‚|¾Ó> ]jŒ• 0px$핸 ˜Ð“¦÷&%3 [5,6].

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:r 7HëH\"fH ƒ™èZOܼ–Ð Al2O₃\ 0.5% ]tq_ Ä»

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о¢§ (Eu)`¦•¸içôÇ ĺ8\¦ ëߖ[þt#Q z´+«> %i. r«Ñ

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6 x %i“¦, Al2O₃&ñ ?/\ Eu³⁺–Ð •¸iç)a כ `¦›'a¹1Ï

l 0AK ŸížÐÀÒpW1‚Û¼ (photoluminescence)\¦ 8£¤&ñ

%i. #Œl"f Ä»–о¢§ +3_ s“:r (Eu³⁺)“Ér„C•¸ 4f?/\"f „ \-t „s #Œ À1ÏçߖҐoܼ–Ð µ1ÏFgôÇ [7,8]. ¢¸ôÇ Eu³⁺_ 4f-4f „s\ _ôÇ ŸížÐÀÒpW1‚Û¼ µ1Ï F

gBj&m7£§“Ér¸ú˜ [O"î÷&#Q4Re” [9].

Eu³⁺_ ŸížÐÀÒpW1‚Û¼_ :£¤$í ×æ@/gA“ (symme- try factor)\¦s6 x #Œ õƒ Al2O3&ñ ?/\ •¸içs ÷&

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Ht #ŒÂÒ\¦SX‰“ H z´+«>`¦ ú'Ÿ %i. sכ “Ér α- Al2O3:Eu³⁺ &ño•¸ †‡\  Eu³⁺_ 0Au@/gA (site symmetry) o\¦SX‰“½+É Ãº e” [10,11]. 7£¤,·ú˜ÀÒ p

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é

¶_ qìø̈́@/gA (asymmetry) ½¨›¸ ´ú§tHכ s



 [12].

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:rƒ½¨\"fHƒ™èZOܼ–Ð ]j›¸ôÇ Al2O3:Eu³⁺_ ŸížÐ À

ÒpW1‚Û¼\"f 1400 ^◦C &ñ•¸t_ “¦“:r #Qu´aA (an- nealing) ´òõ\ @/K tFKt ˜Ð“¦)a  \O#Q s z´ +

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>`¦Ãº'Ÿ > ÷&%3.

II. ÷mÇ]Mö Uês0nÉ

1. ŽìÅ}º0nÉùp§ T“ÓޔX¢ Al₂O₃:Eu³⁺ <gº

Al₂O₃:Eu³⁺`¦ Fig. 1õ °ú s ƒ™èZOܼ–Ð ½+Ë$í

%i. ƒ™èZOܼ–Ð ½+Ë$í l 0AK íߖo]j (oxi- dizer); Al(NO3)·9H2O, Eu(NO3)3 ü< ƒ™è]j (fuel);

CO(NH₂)₂\¦ 3  7£xÀÓú {Œ™” qs&\ —¸¿º †<Ê a

 6 xKr(. sM: íߖo]jü< ƒ™è]j_ o†<Æ|¾Ó:r (sto- ichiometry)`¦ >íߖ½+É M: |9™è"é¶_ s“:rú (va- lency)H Áºr %i. Õª sÄ»H ƒ™èìøÍ6£xs {9#Q±ú˜ M:

Fig. 1. (Color online) Flow chart for the preparation of Al2O3:Eu³⁺.

N2Û¼–Ð @/l ×æ\ ~½Óئ÷&l M:ëHs. Õªo“¦ s z´ +

«>\"fH Eu 0.5%_ ]tq (mole ratio) ÷&•¸2Ÿ¤yŒ•yŒ• r

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0q (gel) ©œI ÷&“¦ Õª Êê 2œí 1lxîߖ ƒ™è #Œ ëߖ[þt#Q” r

«ÑH ¸ÏŠÒo_ ìr´ú˜+þAI–Ð Òqt$í÷&%3. sXO> ëߖ[þt#Q

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´aA “:r•¸H yŒ• 500 ^◦C, 600 ^◦C, 800 ^◦C, 900 ^◦C, 1000

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%i. 8£¤&ñ yŒ••¸ #30A (2θ)H 10^◦ ÂÒ' 90^◦t–Ð 

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×¼  ñ 46-1212ü< q“§Ùþ¡.

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Table 1. Comparisons between d-values of XRD experiment and thoses of JCPDS card for α-Al2O3.

JCPDS card No. 46-1212 XRD Experiment data

(α-Al2O3) (α-Al2O3:Eu³⁺)

d (˚A) Intensity h k l d (˚A) 2θ Intensity

(%) (arb.units)

3.4797 45 0 1 2 3.4688 25.66 336.4

2.5508 100 1 0 4 2.5461 35.22 514.3

2.3794 21 1 1 0 2.3756 37.84 214.1

2.1654 2 0 0 6 2.1563 41.86 29.8

2.0853 66 1 1 3 2.0824 43.42 537.1

1.9643 1 2 0 2 1.9681 46.08 19.7

1.7400 34 0 2 4 1.7385 52.6 205.6

1.6015 89 1 1 6 1.6004 57.54 409.4

1.5466 1 2 1 1 1.5457 59.78 21.9

1.5150 2 1 2 2 1.5141 61.16 24.9

1.5110 14 0 1 8 1.5105 61.32 59.9

1.4045 23 2 1 4 1.4037 66.56 145.1

1.3737 27 3 0 0 1.3732 68.24 250.2

1.3359 1 1 2 5 1.3363 70.4 17.7

1.2755 2 2 0 8 1.2749 74.34 21.4

1.2391 29 1 0 10 1.2387 76.9 74.9

1.2343 12 1 1 9 1.2344 77.22 77.0

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Figure 2H 1200 ^◦C\"f 2rçߖ 1lxîߖ #Qu´aA`¦Ãº'ŸôÇ α-Al₂O₃:Eu³⁺ r«Ñ\ @/K "loÛ¼‚r]X ìr$3ôÇ õ\¦

˜

Ð#Œïr. sכ “Ér “¦“:r 6 xÖ6x©œI\"f ½+Ë$í t ·ú§“¦•¸

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™èZOܼ–Ð α-Al2O₃:Eu³⁺\¦ ëߖ[þtú e”H כ `¦




·p. 1000 ^◦CÂÒ' 1400 ^◦Ct 2rçߖ 1lxîߖ #Qu´aA`¦ Ã

º'ŸôÇ α-Al₂O₃:Eu³⁺ r«ÑH —¸¿º 1lx{9ôÇ "loÛ¼‚r]X ì

r$3 õ x9 ŸížÐÀÒpW1‚Û¼ ©œìr$3 õ\¦%3#Q @/

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ð&hܼ–Ð 1200 ^◦C\"f #Qu´aA %ƒoôÇ r«Ñ\¦ Fig. 2\

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&ñ€tú\ Ér r]X€çߖ o\¦ Table 1\
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. sכ “Ér JCPDS ×¼  ñ 46-1212ü< q“§ #Œ ìr$3 ô

Ç õ z´+«>°úכõ ¸ú˜ {9u %i.

Fig. 2. X-ray diffraction pattern of the annealed α- Al₂O₃:Eu³⁺ at 1200 ^◦C for 2 hours.

Figure 3“Érƒ™èZOܼ–Ð ½+Ë$íôÇ Al2O3:Eur«Ñ\¦ “:r•¸ 500 ^◦C, 600 ^◦C, 700 ^◦C, 800 ^◦C, 900 ^◦C, 1000 ^◦C, 1100

◦C, 1200 ^◦C, 1300 ^◦C\"f yŒ•yŒ• 2rçߖ 1lxîߖ #Qu´aA “¦

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loÛ¼‚r]XìrôÇ õ\¦ ˜Ð#Œïr. 1400 ^◦C\"f 2rçߖ 1

l

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HÒqt|ÄÌ`¦ %i. {9ìøÍ&hܼ–Ð ·ú˜ÀÒp
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