Formation of Branched Carbon Nanotube Structure by Additional Supply of Growth Catalysis
Akira TAKAHASHI*, Yohei SAKAMOTO*, Toshiro KASUYA* and Motoi WADA* (Received April 20, 2007)
Growth catalysis coating prior to a plasma enhanced chemical vapor deposition realizes homogenous carbon nanotube (CNT) layer. Sputter deposition of Ti, Fe, Mo and Ni on Si substrates modifies the deposited carbon nanostructure on the substrates immersed in a H2 diluted CH4 plasma sustained by a radio-frequency magnetron discharge. Among the tested materials, Ni has realized the smallest size nanostructure. Proper bias voltage applied to the Si substrate helped carbon nanotube align perpendicularly to the substrate. Further addition of Ni catalysis during plasma deposition process has formed a peculiar structure of the grown carbon nanotubes having several branches directed to the radial direction. Procedures to supply Ni catalysis directly affected the structure of the formed nanaotubes.
Key words: carbon nanotube, carbon nanowall, plasma material synthesis
ࠠࡢ࠼㧦ࠞࡏࡦ࠽ࡁ࠴ࡘࡉ㧘ࠞࡏࡦ࠽ࡁ࠙ࠜ࡞㧘ࡊ࠭ࡑวᚑ
ᚑ㐳⸅ᇦㅊടଏ⛎ߦࠃࠆ᮸ᨑ⁁⚛࠽ࡁ࠴ࡘࡉ᭴ㅧߩᒻᚑ
㜞ᯅ ℭ*㧘ဈᧄ 㓁ᐔ*㧘☺⼱ ବ㇢*㧘↰ ర*
ߪߓߦ
⚛ߩห⚛ߣߒߡߪ㧘߽ߣ߽ߣ⚛ේሶ߇ᱜ྾
㕙⁁ਃᰴర⊛ߦ
sp3
⚿วߒߚ࠳ࠗࡗࡕࡦ࠼ߣ㧘⚛ේሶ߇ⷺᒻⱎߩᎽ⁁ߦ
sp2
⚿วߒߚੑᰴరߩࠪ࠻㧔ࠣࡈࠚࡦࠪ࠻㧕߇ᐔⴕߦⓍߺ㊀ߥߞߚࠣ
ࡈࠔࠗ࠻ߩሽ߇⍮ࠄࠇߡߚ߇㧘⚛ߩᣂߚߥ
╙ਃߩห⚛ߣߒߡࡈࡦ㧔
fullerene
㧕߇⊒ߐࠇ 1)㧘ߘߩᓟࡈࡦߩᄙ㊂วᚑᴺ߇ߟ߆ߞ ߡ㑆߽ߥߊ㧘ࠣࡈࠚࡦࠪ࠻߇ੑ߆ࠄᢙචጀߦ߽
㊀ ߥ ߞ ߚ ᭴ ㅧ ߩ ᄙ ጀ ࠞ ࡏ ࡦ ࠽ ࡁ ࠴ ࡘ ࡉ 㧔
Multi-walled carbon nanotube, MWNT
㧕߇⊒ߐࠇ ߚ 2)㧚߹ߚ㧘ߘߩੑᐕᓟߦߪࠣࡈࠚࡦࠪ࠻߇৻ጀߛߌ╴⁁ߦ㐽ߓߚනጀࠞࡏࡦ࠽ࡁ࠴ࡘࡉ 㧔
Single-walled carbon nanotube, SWNT
㧕߇⊒ߐࠇ
ߚ㧚ᦝߦᦨㄭߦߥߞߡ
2
ᰴరࠞࡏࡦ࠽ࡁ᭴ㅧߢࠆࠞࡏࡦ࠽ࡁ࠙ࠜ࡞㧔
Carbon nanowall, CNW
㧕 ߩሽ߽⏕ߐࠇߚ㧚
CNT
ߪ㧘ࠣࡈࠚࡦߣ߫ࠇࠆ⚛ⷺ✂㕙㧔ࡂ࠾ࠞࡓ᭴ㅧߩࡀ࠶࠻㧕߇࠽ࡁࡔ࠻࡞ࠝ࠳ߩ⋥
ᓘߩ╴ߦਣ߹ߞߚࠪࡓࠬߩਛⓨߩ▤㧔࠴ࡘ
ࡉ㧕ߢࠆ㧚㐳ߐߪ
10 µm
ࠍ߃ࠆߎߣ߽ᄙߊ㧘ᄢ ߈ߥࠕࠬࡍࠢ࠻㧔㐳ߐ⋥ᓘ㧕Ყࠍ߽ߟ㧚CNT
ߪ㧘ࠣࡈࠚࡦߩਣᣇ㧔⋥ᓘߣࠞࠗ࠹ࠖ㧕ߦଐ ሽߒߡ㧘㊄ዻߦ߽ඨዉߦ߽ߥࠆ․⇣ߥ㔚ሶ⊛ᕈ⾰
ࠍ␜ߒ㧘ജቇ⊛ߦߪᦨ㜞ߩᒁᒛᒝᐲߣᄢ߈ߥࡗࡦࠣ
₸㧔❑ᒢᕈ₸㧕ࠍߔࠆ㧚⊒⋥ᓟ߆ࠄᵈ⋡ߐࠇߚ
CNT
ߪ㧘࠽ࡁ࠹ࠢࡁࡠࠫߩઍ⊛ߥᣂ⚛᧚ߣߒߡ ᧂߛߦᄙߊ⎇ⓥ߇ⴕࠊࠇߡࠆ㧚࠽ࡁࠝ࠳ߩ⋥ᓘߢࠆߎߣߦട߃㧘․⇣ߥ‛ℂ․ᕈࠍߒߡࠆ ߚ㧘ߘߩ࠺ࡃࠗࠬ߳ߩᔕ↪น⢻ᕈ߽ᄙጘߦਗ਼ߞߡ
*Graduate School of Engineering㧘 Doshisha University㧘 Kyoto.
Telephone: +81-774-65-6823㧘 Fax:+81-774-65-6804㧘 E-mail: [email protected]
ࠆ㧚ඨዉᕈࠍߔࠆ
SWNT
ߩࡃࡦ࠼ࠡࡖ࠶ࡊࠍ↪ߒߚࠩߥߤߩశቇ⚛ሶ㧘⋥ᓘ߇
1 nm
⒟ᐲ ߢඨዉᕈߣ߁․ᓽࠍ↪ߒߚCNT FET
㧔field emission transistor
㧕ߥߤߩ㔚ሶ⚛ሶ㧘࠽ࡁࠨࠗ࠭ߢ㜞 ዉ㔚ᕈࠍ␜ߔ․ᓽࠍ↪ߒߚLSIᓸ⚦㈩✢㧘వ┵߇㍈ߎߣࠍ↪ߒߚ
FED
㧔field emission display
㧕ߩ 㔚⇇ဳ㔚ሶḮ3,4)㧘ᩏဳࡊࡠࡉ㗼ᓸ㏜SPM
ߩ⍴㊎㧘SWNT
ߩౝㇱߦC
60ߥߤߩࡈࡦࠍౝ൮ߒߚࡇࡐ࠶࠻㧔
peapod
㧕ߦࠃࠆ᳓⚛⾂⬿㧘ߘߩઁࡃࠗࠝࡦࠨ㧘ⶄว᧚ᢱߥߤᐢಽ㊁߳ᔕ↪
߇ᦼᓙߐࠇࠆ㧚ߎࠇࠄᔕ↪ಽ㊁ߦ߅ߌࠆ
CNT
․ᕈߪ ᓢޘߦ⸃ߐࠇߟߟࠆ߇㧘ታⵝߦ߅ߡ㊀ⷐߥCNT
ߩ㈩⟎ᓮᚑ㐳ᣇะᓮߥߤߩቯ⊛ߥᚻᴺ ߪᧂߛ⏕┙ߐࠇߡߥ㧚CNT
ߣห᭽ߩᚑ㐳᧦ઙߦࠃߞߡCNW
߇ᒻᚑߐࠇ ࠆ႐ว߽ࠆ㧚CNW
ߩ႐ว㧘ࠣࡈࠚࡦࠪ࠻߇ ᢙᨎ㨪100
ᨎ⒟ᐲ㊀ߥߞߡ㧘ෘߐᢙ࠽ࡁࡔ࠻࡞߆ ࠄᢙච࠽ࡁࡔ࠻࡞ߩ㧞ᰴరߦ߇ࠆ᧼⁁ߩ࠽ࡁ᭴ㅧ‛ࠍ᭴ᚑߒ㧘ၮ᧼ߦኻߒߡ߶߷ု⋥ߦ┙ߞߚᒻߢ ᚑ㐳ߒߡࠆ㧚㔚⇇㧔
FE: Field emission
㧕ߦ߅ߡߪ
CNT
ߩ․ᕈࠃࠅ߽⦟ߣ߁ߎߣ߽ႎ ๔ߐࠇߡࠆ㧚CNT/CNW
ߩ↢ᚑᣇᴺߣߒߡߪ㧘ࠩࠕࡉ࡚ࠪࡦᴺ㧘ࠕࠢ㔚ᴺ㧘ࡊ࠭ࡑᡰេൻቇ᳇⋧
ᚑ㐳
PECVD)
ᴺ╬߇ജߢࠆ߇㧘․ߦ᭴ㅧࠍ↢ᚑߔࠆ೨ߦၮ᧼ߦ⫳⌕ߔࠆ⸅ᇦߩലᨐ߇㊀ⷐߢ
ࠆߣႎ๔ߐࠇߡࠆ 5)㧚ᧄ⎇ⓥߢߪ
PECVD
ᴺߦ ࠃࠅ↢ᚑߐࠇࠆ⚛ၸⓍጀߩ࠽ࡁ᭴ㅧ߇㧘⸅ᇦ᧚ᢱ ߩଏ⛎ߦࠃߞߡߤߩࠃ߁ߦᄌൻߔࠆ߆ࠍ⺞ᩏߒߚ㧚․ߦ࿁ߪ㧘߹ߢၸⓍጀᒻᚑߩ೨ಣℂߣߒߡⴕࠊ ࠇߡ߈ߚ⸅ᇦଏ⛎ࠍ㧘ࠬࡄ࠶࠲⫳⌕ߦࠃߞߡၸⓍਛ ߦ߽ⴕߞߚ႐วߦ↢ߓࠆ㧘․ᓽ⊛ߥ࠽ࡁ᭴ㅧᒻᚑߦ ߟߡႎ๔ߔࠆ㧚
2㧚 ታ㛎ⵝ⟎㩷 㩷
㩷ⵝ⟎࿑ࠍ
Fig. 1
ߦ␜ߔ㧚ⵝ⟎ኸᴺߪౝᓘਅ㔚ᭂㇱ ߦᄖᓘ46 mm
㧘ౝᓘ33 mm
ߩࡦࠣ⏛⍹ߣ⋥ᓘ㧢mm
ߩᩇဳ⏛⍹߇⸳⟎ߐࠇ㧘ਛᔃઃㄭߢല₸⦟ߊࠫࠞ࡞ࠍ↢ᚑߔࠆ㧚ᧄ⎇ⓥߢߪ⸅ᇦଏ⛎ߩᓮࠍ
ⴕ߃ࠆࠃ߁㧘ᣢߦ
CNT
↢ᚑߦଏߐࠇ㧘ല₸߇㜞ߣ ႎ๔ߐࠇߡࠆRF
ࡑࠣࡀ࠻ࡠࡦ㔚ࠍណ↪ߒߟߟ6)㧘
CNT
ၸⓍ࠲ࠥ࠶࠻߳ߩ⸅ᇦଏ⛎ߦኻߒߡᓮ⥄↱ᐲ߇㜞ߊߥࠆࠃ߁㧘ᐔ᧼ဳࡑࠣࡀ࠻ࡠࡦ᭴ㅧߣ ߒߡࠆ㧚߹ߚ㧘
DC
ࡃࠗࠕࠬߪਈ߃ߕ㧘㔚Ḯ߆ࠄ⋥ធኈ㊂⚿วߦࠃࠅ㧘
RF
㔚ജࠍଏ⛎ߒߚ㧚
RF
㔚ᭂߣࠞࡏࡦ࠽ࡁ᭴ㅧࠍ↢ᚑߔࠆSi
ၮ᧼࠲ࠥ࠶࠻ߩ〒㔌ߪ
20 mm
ߦߚࠇߡߡ㧘ᦨᄢജ
720 W
ߩ⿒ᄖ✢ユടᾲဳࡅ࠲߇ขࠅઃߌࠄࠇߡࠆ㧚⿒ᄖ✢ߦࠃࠅ㧘ၮ᧼ࠍ㔚᳇⊛ߦ⛘✼ߒ ߚ⁁ᘒߢᦨ㜞᷷ᐲ
800
͠ࠍ⛽ᜬߢ߈ࠆ㧚ၮ᧼ߦߪ㔚ࠍ⛽ᜬߔࠆ㜞ᵄ㔚Ḯߣߪߦޔ⋥ᵹ㔚ࠍශട ߔࠆߎߣߦࠃࠅ㧘ࠪࠬౝߦࠆࠗࠝࡦߩࠛࡀ࡞ࠡ
ᓮࠍⴕ߁㧚
ේᢱࠟࠬ㧘߮ࠬࡄ࠶࠲ࡦࠣ↪㔚ࠟࠬߪࠬࡠ
ࠢࡃ࡞ࡉࠍㅢߓߡଏ⛎ߔࠆ㧚⋥✢ዉ┵ሶవ
┵ߦขࠅઃߌࠄࠇߚ⸅ᇦ㊄ዻߪ
RF
㔚㔚ᭂߦ⸳⟎ߔࠆߎߣ߇ߢ߈㧘ࠬࡄ࠶࠲ࡦࠣ⚳ੌᤨߦߪࠨࠗ
࠼ࠕࡓߦᒁ߈ᚯߐࠇߡࡊ࠭ࡑ㗔ၞᄖߦᜬߐ ࠇࠆ㧚
CNT
↢ᚑᤨߩㆇォࠍᢙPa
ᢙචಽߢⴕ߁ߚ㧘 ࡃࠗ࠻ࡦO-
ࡦࠣࠍ↪ߡ߅ࠅ㧘࠲ࡏಽሶࡐࡦࡊ ߦࠃࠆឃ᳇ߢ㆐⌀ⓨᐲߪ4x10
-4Pa
ߢࠆ㧚㩷 㩷
Fig.1. Schematic diagram of the experimental apparatus.
3㧚 ታ㛎ᣇᴺ
3.1⸅ᇦ⒳ߦࠃࠆ᭴ㅧᄌൻ
⸅ᇦߩ⒳㘃ࠍᄌൻߐߖࠆߎߣߦࠃࠆࠞࡏࡦ࠽ࡁ
᭴ㅧߩᚑ㐳ᄌൻࠍⷰኤߒߚ㧚ᚑ⤑᧦ઙߣߒߡ㧘ၮ
᧼ࠍ
600
͠߹ߢടᾲߒ㧘࠴ࡖࡦࡃౝߦࠕ࡞ࠧࡦ4 Pa
ࠍዉߒߚᓟ㧘RF
㔚ജ(13.56MHz) 150 W
ࠍᛩߒ㧘
5
ಽ㑆ࡑࠣࡀ࠻ࡠࡦࠬ࠶ࡄ࠲ࠍⴕߞߡ㧘⸅ᇦ ࠍၮ᧼ߦ⫳⌕ߔࠆ㧚ߘߩᓟ㧘ࠕ࡞ࠧࡦ4 Pa
ࠍ⛽ᜬߒ ߚ⁁ᘒߢ3
ಽ㑆ߩ㔚ભᱛᤨ㑆ࠍขࠆ㧚࠴ࡖࡦࡃౝߦࡔ࠲ࡦ
5 Pa
ࠍዉߒ㧘RF
㔚ജ200 W
ࠍᛩߒߡ㧘
PECVD
ᴺߦࠃࠅ30
ಽ㑆ߩᚑ⤑ࠍⴕ߁㧚ߎߩ᧦ઙࠍၮḰߣߒߡ
Ni
㧘Ti
㧘Mo
㧘Fe
ߣ⸅ᇦ⒳ࠍᄌ ൻߐߖߚ㧚
3.2⸅ᇦ⫳⌕ࡄ࠲ࡦߩᄌൻ
⸅ᇦ⫳⌕ࡄ࠲ࡦࠍᄌൻߐߖࠆߎߣߦࠃࠅ↢ߓࠆ
ࠞࡏࡦ࠽ࡁ᭴ㅧߩᚑ㐳ᒻᘒߩᄌൻࠍⷰኤߒߚ㧚
2.1
ߣหߓᚻ㗅ߢ⸅ᇦࠍ⫳⌕ߒߚᓟ㧘᳓⚛3 Pa
ࠍ⛽ᜬߒߚ⁁ᘒߢ
3
ಽ㑆ߩ㔚ભᱛᤨ㑆ࠍขࠆ㧚࠴ࡖ ࡦࡃౝࠍࡔ࠲ࡦ5 Pa
㧘᳓⚛3 Pa
ߢో8 Pa
ߣߒ㧘࠴ࡖࡦࡃߦኻߒߡ
-10 V
ߩ⋥ᵹ⽶ࡃࠗࠕࠬࠍශട ߒߚ㧚 ᛩRF
㔚ജࠍ200 W
ߣߒߡ㧘PECVD
ᴺߦ ࠃࠅ30
ಽ㑆ߩᚑ⤑ࠍⴕ߁㧚ߎߩ᧦ઙࠍၮḰߣߒߡ㧘 ᚑ⤑ਛߦ⸅ᇦ᧚ᢱࠍ࠴ࡖࡦࡃ┵ߦ⒖േߐߖߡ⫳⌕ࠍᛥߔࠆ႐วߣ㧘
CNT
ᚑ㐳ਛ߽㔚ᭂߩߦ⸅ᇦࠍᜬߒߡଏ⛎ߒ⛯ߌࠆ႐วߦߟߡ㧘ࠨࡦࡊ࡞
ࠍⴕߞߚ㧚
3.3 ၮ᧼ශടࡃࠗࠕࠬߦࠃࠆ᭴ㅧᄌൻ
2.2
ߩCNT
↢ᚑ᧦ઙ㧘߮⸅ᇦ⫳⌕ಣℂࠍⴕߞߚ ᓟ㧘ၮ᧼ࠍ࠴ࡖࡦࡃߦኻߒߡ0 V
㧘-10 V
㧘-20 V
㧘-50 V
ߦࡃࠗࠕࠬߒߚ⁁ᘒߢRF
㔚ജ200 W
ߩPECVD
ᴺߦࠃࠆ30
ಽ㑆ߩᚑ⤑ࠍⴕߞߚ㧚ߎߩ᧦ઙࠍၮḰߣߒߡ㧘 ⸅ᇦࠍࠬࡄ࠶࠲ࡦࠣߩᓟޔᚑ⤑ᤨ
ߦ㧘࠴ࡖࡦࡃ┵ߦ⒖േߐߖ⫳⌕ࠍᛥߔࠆ႐วߣ ߘߩ߹߹㔚ᭂߩߦᜬߒߚ⁁ᘒߦߒߚ߹߹ߦߔࠆ ႐วߦߟߡ
CNT
᭴ㅧᄌൻࠍⷰኤߒߚ㧚
㧚 ⚿ᨐ߅ࠃ߮⠨ኤ
4.1 ⸅ᇦ⒳ߦࠃࠆ᭴ㅧᄌൻ
Ni
ࠍ⸅ᇦߣߒߚ႐วߩࠞࡏࡦ࠽ࡁ᭴ㅧߩFE-SEM
ࠍFig. 2 (a)
ߦ㧘⸅ᇦ߇Fe
ߩᤨߩࠞࡏࡦ࠽ࡁ᭴ㅧߩ
FE-SEM
ࠍFig. 2 (b)
ߦ㧘⸅ᇦ߇Ti
ߩߣ߈ߩࠞࡏࡦ࠽ࡁ᭴ㅧߩFE-SEM
ࠍFig. 2 (c)
ߦ㧘⸅ᇦ߇Mo
ߩߣ߈ߩࠞࡏࡦ࠽ࡁ᭴ㅧߩFE-SEM
ࠍFig. 2 (d)
ߦߘࠇߙࠇ␜ߔ㧚Ni
ࠍ⸅ᇦߣ ߔࠆᤨߪ߇50 nm
⒟ᐲߩࠞࡏࡦ࠽ࡁ᭴ㅧ߇ᒻ ᚑߐࠇߡࠆߩ߇ⷰኤߢ߈ࠆ㧚Fe
⸅ᇦߦኻߒߡߪ⋥ᓘ
50 nm ~ 80 nm
⒟ᐲߩ࠴ࡘࡉ⁁ߩ߽ߩ߇ᚑ㐳ߒ ߡࠆTi
⸅ᇦߩᤨߦߪ40 nm ~ 55 nm
⒟ᐲߩ࠴ࡘࡉ⁁ߩ߽ߩ߇ࡦ࠳ࡓߦᚑ㐳ߒߡࠆ㧚
Mo
⸅ᇦߩᤨߪ
FE-SEM
ߢߩⷰኤߢࠆ㒢ࠅ࠴ࡘࡉᒻ⁁߹ߚߪო⁁ߩ࠽ࡁ᭴ㅧ߇⏕ߢ߈ߥ߆ߞߚ㧚߆ࠄ
್ᢿߒߡ㧘ࠣࡈࠔࠗ࠻ߣߒߡၸⓍߒߡࠆน⢻ᕈ ߇㜞㧚
Ni
⸅ᇦ㧘Fe
⸅ᇦߣTi
⸅ᇦߩ࠽ࡁ᭴ㅧࠍ ᲧセߔࠆߣFe
㧘Ni
⸅ᇦߩ߶߁߇ᐞಽၮ᧼ߦု⋥ߦ ᚑ㐳ߒߡࠆࠃ߁ߦ߃ࠆ㧚߹ߚ㧘ㅀߒߚࠞࡏ ࡦ࠽ࡁ᭴ㅧߩ⋥ᓘ߹ߚߪߪ㧘Ti
㧘Fe
㧘Ni
ߩ㗅ߢ ዊߐ㧚ߎࠇߪේሶ㊂ߦ߶߷ᔕߓߚᄌൻߢࠆ㧚
(a) nickel (b) iron
(c) titanium (d) molybdenum
(b)
Fig.2. FE-SEM images of carbon nanostructure for different catalysts.
4.2 ⸅ᇦ⫳⌕ࡄ࠲ࡦߩᄌൻ
ᚑ⤑ᤨߦࡑࠣࡀ࠻ࡠࡦࠬࡄ࠶࠲ࠛࠕ߆ࠄ⸅ᇦࠍ ᄖ ߒ ߡ ࠞ ࡏ ࡦ ࠽ ࡁ ᭴ ㅧ ࠍ ↢ ᚑ ߐ ߖ ߚ ᤨ ߩ
FE-SEM
ࠍFig. 3
ߦ␜ߔ㧚߹ߚ㧘Fig. 3
ߩၸⓍ‛ࠍ↢ᚑߔࠆ೨ߩ⁁ᴫߣߒߡ㧘࠴ࡖࡦࡃౝߦ
Ar 4 Pa
ࠍዉߒޔᛩRF-
㔚ജ150 W
ࠍ5
ಽ㑆ߩࠬࡄ࠶࠲ࡦࠣࠍⴕߞߚ⋥ᓟ㧘ⵝ⟎߆ࠄขࠅߒߡ
FE-SEM
ߢⷰኤߒߚߣ߈ߩ᭽ሶࠍFig. 4
ߦ␜ߔ㧚ၮ᧼ߦኻߒ ߡု⋥㈩ะߒߚCNT
߇Si
ၮ᧼ߦ↢ᚑߐࠇߡࠆ ߎߣ߇Fig. 3
߆ࠄಽࠆ㧚࠴ࡘࡉߩ⋥ᓘߪ⚂60 nm
ߢࠅ㧘
Fig. 4
ߦⷰኤߐࠇࠆၮ᧼ߦࠬࡄ࠶࠲⫳⌕ߐࠇߚ
Ni
⸅ᇦߩᄢ߈ߐߣ߶߷╬ߒ㧚࠽ࡁ࠴ࡘࡉᚑ㐳ᤨਛߦ߽ࠬࡄ࠶࠲ࠛࠕߦ⸅ᇦ ࠍࠇ㧘ᚑ㐳ߐߖߚᤨߩ
FE-SEM
ࠍFig. 5
ߦ␜ߔ㧚ု⋥㈩ะߒߚ
CNT
߆ࠄߐࠄߦᣇะߦ㧘ࠆ৻ቯߩ㑆㓒ߢᩮర߆ࠄవ┵߹ߢ
CNT
߇ᚑ㐳ߒߡࠆߩ ߇⏕ߢ߈ࠆ㧚ߐࠄߦ⚦߆ߊࠆߣ㧘⁁ߦᚑ㐳 ߒߡࠆCNT
ߪ120°
߹ߚߪ60°
ߩⷺᐲ㑆㓒ࠍ߽ߞߡ ᚑ㐳ߒߡࠆߩ߇⏕ߢ߈ࠆ㧚ߎࠇߪⷺࠣࡈࠚ ࡦߩ120°
ߣኻᔕߒߡࠆ㧚߹ߚ㧘ᨑߩవ┵ㇱߪᐙㇱ ߣᲧセߒߡ⚦ࠃ߁ߦ߃ࠆ㧚ታ㓙ߦ⚦ࠃ߁ߥࠄ㧘 ㅢᏱߩMWNT
ߣᲧセߒߡ㧘ࠃࠅఝࠇߚ㔚ሶ․ᕈࠍߒߡࠆน⢻ᕈ߽ࠆ㧚
Fig. 5
ߦࠄࠇࠆࠃ߁ߥ᮸ᨑ⁁CNT
᭴ㅧߪ࠽ࡁ࠴ࡘࡉ㕙ߦ
Ni
߇ઃ⌕ߒ,
ᣂߚߥᚑ㐳ᩭߩᒻᚑߣߥ ߞߡᨑㇱಽߩિ㐳ࠍଦߒߚ߽ߩߣ⠨߃ࠄࠇࠆ.
ߘߎ ߢCNT
ᚑ㐳ᦼ㑆ߩNi
ଏ⛎ࠍᓮߔࠆߎߣߦࠃࠅ㧘 ታ㓙ߦNi
ଏ⛎߇ߎߩ᭴ㅧߩቯⷐ࿃ߢࠆ߆⏕ߔࠆታ㛎ࠍⴕߞߚ
.
ᚑ⤑ᤨߩᦨೋߩ5
ಽ㑆㧘ࠬࡄ࠶࠲ࠛࠕߦ⸅ᇦࠍ⸳⟎ߒߚᤨߩࠞࡏࡦ࠽ࡁ᭴ㅧ
ߩ
FE-SEM
ࠍFig. 6
㧔a
㧕ߦ㧘ᦨᓟߩ5
ಽ㑆ࠬࡄ࠶࠲ࠛࠕߦ⸅ᇦࠍ⸳⟎ߒߚᤨߩࠞࡏࡦ࠽ࡁ᭴ㅧ
ߩ
FE-SEM
ࠍFig. 6 (b)
ߦ␜ߔ㧚ೋߦNi
ࠍଏ⛎ߒߚ႐วߦߪ㧘⧯ᐓߩੂࠇߪࠆ߽ߩߩ㧘߶߷㈩ะ ߒߚ
CNT
ߩవ┵ㇱಽ߇᷹ⷰߐࠇࠆ㧚ઁᣇ㧘ᦨᓟߩ5
ಽ㑆ߦଏ⛎ߒߚߣ߈ߦߪ㧘వ┵ㇱߦ᮸ᨑൻ߇᷹ⷰߐ ࠇࠆ㧚ߚߛߒ㧘Fig. 5
ߦᲧߴߡᨑㇱಽߩᚑ㐳߇㗼⪺ߢήߊ㧘
Ni
ઃ⌕ᓟߩᚑ㐳ᦼ㑆߇ਇචಽߢߞߚน⢻ᕈ߇㜞㧚ᦝߦታ㛎᧦ઙࠍᐢߍ㧘ᨑㇱߩᒻᚑㆊ⒟ߣ ᚑ㐳ㆊ⒟ߦಽߌߚ♖ኒߥ⺞ᩏ߇ᔅⷐߢࠆ㧚
Fig.3. FE-SEM images of CNTs grown on Si substrate
prepared with sputter deposited Ni.
Fig.4. FE-SEM images showing Ni deposited on Si substrate prepared as the starting condition to grow
aligned CNTs by PECVD process.
Fig.5. FE-SEM images of carbon nanostructure prepared with Ni sputtering supply onto the substrate during CNT
growth.
4.3 ၮ᧼ශടࡃࠗࠕࠬߦࠃࠆ᭴ㅧᄌൻ
Fig. 3
߿Fig. 5
ߦ␜ߔ⚛࠽ࡁ᭴ㅧࠍᚑߔࠆ 㓙ߦ⸳ቯߒߚSi
ၮ᧼ߦኻߔࠆ⋥ᵹࡃࠗࠕࠬߪ㧘㔚 ኈེო㕙ߦኻߒߡ-10V
ߢ࿕ቯߢߞߚ㧚ߎߩࡃࠗࠕࠬ㔚ࠍ
-20V
ߦ⸳ቯߒߚᤨߩࠞࡏࡦ࠽ࡁ᭴ㅧߩ
FE-SEM
ࠍFig. 7 (a)
㧘-50V
ߦ⸳ቯߒߚᤨߩࠞࡏࡦ࠽ࡁ᭴ㅧߩ
FE-SEM
ࠍFig. 7 (b)
ߦ␜ߔ㧚ࡃࠗࠕࠬ߇
-10V
ߢၮ᧼ߦ㆐ߔࠆࠗࠝࡦࠛࡀ࡞ࠡ߇ㆡᒰߥߚ㧘ࠞࡏࡦ࠽ࡁ᭴ㅧߪẩࠇߕߦᚑ㐳 ߒ㧘ߐࠄߦ᮸ᨑߩ᭴ㅧ߇↢ᚑߐࠇߡ߽⎕უߐࠇ ߥ㧚㔚߇
-20V
㧘-50V
ߦߥࠆߣ㧘ਔᣇߣ߽CNT
ᒻᚑ߇CNW
᭴ㅧߦᄌൻߒߡࠆߩ߇⏕ߢ߈ࠆ㧚 ᦝߦᲧセࠍⴕ߁ߣ߶߷ห᭽ߦ߃ࠆWall
߇㧘-50V
ᤨߦ߅ߡ⧯ᐓ⚦߆ࠃ߁ߦ߽ⷰኤߐࠇߚ㧚߹ߚ㧘 ਔ႐วߦߟߡ㧘
CNW
ߩო㕙ߪ᮸ᨑ⁁ߩCNT
ߩ⁁ߦᚑ㐳ߒߡࠆⷺᐲ㑆㓒ߩ߶߷
120
q߹ߚߪ60
qߩⷺᐲߢߩო㕙ห჻߇ߟߥ߇ߞߡࠆߩ߇⏕ߢ߈ߚ㧚
Ni
ଏ⛎ᄌൻߦࠃࠆ⏕ߥᏅ⇣ߪ߹ߢ ߩߣߎࠈ⏕ߐࠇߡߥ㧚㧚⚿⸒
ᧄ⎇ⓥߢߪࠞࡏࡦ࠽ࡁ᭴ㅧ⸅ᇦଏ⛎ߩᓇ㗀ࠍ
ⷰኤߔࠆߎߣߦࠃࠅ㧘ࠞࡏࡦ࠽ࡁ᭴ㅧߩᣂ᭴ㅧ ߩ↢ᚑน⢻ᕈࠍ⺞ᩏߒߚ㧚
ع⸅ᇦ䈱⒳㘃䈮ᔕ䈛䈩
CNT
䈱᭴ㅧ䋬↢ᚑኒᐲ䉅ᄌ ൻ䈜䉎䋮㩷 㩷ع
RF-PECVD
ᴺߢߩCNT
↢ᚑߦߪၮ᧼ශടࡃࠗࠕࠬߦㆡᱜ୯߇ࠅ㧘ߘࠇએᄖߩ᧦ઙߢߪ
CNT
ߩ᭴ㅧߪ፣ࠇࠆ㧚
ع ࠞࡏࡦ࠽ࡁ᭴ㅧᚑ㐳ᤨߦ⸅ᇦࠫࠞ࡞ࠍ࠽
ࡁ᭴ㅧ㕙ߦㆡᱜߦଏ⛎ߔࠆߣ㧘᮸ᨑ⁁ࠞ
ࡏࡦ࠽ࡁ᭴ㅧ߇↢ᚑߐࠇࠆ㧚
ع ᮸ᨑ⁁ࠞࡏࡦ࠽ࡁ᭴ㅧߩ⁁ߦᚑ㐳ߒߡ
ࠆᨑㇱಽߩᚑ㐳ߪⷺࠣࡈࠚࡦߩⷺᐲߣห
᭽ߩ⚂
120
q߹ߚߪߘߩඨಽߩⷺᐲ60
qߩ㑆㓒 ߢᚑ㐳ߔࠆ㧚ᣂ࠽ࡁ᭴ㅧߣߒߡ᮸ᨑ⁁
CNT
ࠍ↢ᚑน⢻ߢࠆߎߣ߇ಽߞߚ㧚ߎߩ࠽ࡁ᭴ㅧߪ࠴ࡘࡉߩవ┵
ㇱ߇ᄙߊࠆ․ᓽߩࠆᒻ⁁ߥߩߢᣂߚߥน⢻ᕈࠍ
⒁ߡࠆ㧚ߎߩ᮸ᨑ⁁࠽ࡁ᭴ㅧ߇ߤߩࠃ߁ߥᯏ
᭴ߢ↢ᚑߐࠇߡࠆߩ߆ᦝߦ⎇ⓥࠍ⛮⛯ߔࠆ㧚
⻢ㄉ
ᧄ⎇ⓥߩ৻ㇱߪหᔒ␠ᄢቇ⇇㕙⎇ⓥࡦ࠲ߩᡰេ
ߦၮߠߡⴕࠊࠇߚ㧚
ෳ⠨ᢥ₂
1) H. W. Kroto, J. R.Heath, S. C.O'Brien, R.F. Curl, and R.E.
Smalley, “C60: Buckminsterfullerene, Nature,” 318, 162 (1985).
2) S㧚Iijima, “Helical microtubules of graphitic carbon,” Nature, 354, 56 (1991).
3) V㧚 Derycke, R. Martel, J㧚 Appenzeller and Ph. Avouris,
“Carbon Nanotube Inter- and Intramolecular Logic Gates,”
Nano Lett. 1, 453 (2001).
4) A. Bachtold, P. Hadley, T. Nakanishi and C. Dekker, “Logic circuits with carbon nanotube transistors,” Science, 294, 1317 (2001).
5) Y. Tu, Z. P. Huang, D.Z. Wang, J.G. Wen and Z.F. Ren, Fig.6. FE-SEM images of carbon nanostructures for
different time schedules to supply Ni catalysts.
(a) First 5 minutes (b) Last 5 minutes
Fig.7. FE-SEM images of carbon nanostructure for different substrate bias.
(a) -20V (b) -50V
“Growth of aligned carbon nanotubes with controlled site density,” Appl. Phys. Lett. 80, 4018 (2002).
6) T. Hirata, N. Satake, G. -H. Jeong, T. Kato, R. Hatakeyama, K. Motomiya, and K. Tohji, “Magnetron-type
radio-frequency plasma control yielding vertically well-aligned carbon nanotube growth,” Applied Physics Letters, 83, 1119 (2003).
