Name: seedless growth of bismuth nanowire array via vacuum thermal evaporation
Uploaded: 2015-12-21T13:00:00.000+00:00
Duration: 8 min 58 s
Description: Watch this Scientific Journal Video about Seedless Growth of Bismuth Nanowire Array via Vacuum Thermal Evaporation at JoVE.com

Research is carried out at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-SC0012704.

주의 : 사용하기 전에 모든 관련 물질 안전 보건 자료 (MSDS)를 참조하시기 바랍니다. 나노 물질은 대량의 대응에 비해 추가 위험이있을 수 있습니다. 공학적 관리 (흄 후드) 및 개인 보호 장비의 사용을 포함, 나노 물질 덮인 기판을 처리 할 때 모든 적절한 안전 방법을 사용하십시오 (보안경, 장갑, 실험실 코트, 전체 길이 바지, 신발 - 발가락을 휴관). 1. 준비 작업 <ol><li> 증착 시스템의 제조 <ol><li> 대기압에 증착 챔버와 벤트 챔버를 연다. 벤트 자동 대기 압력 챔버를 배출 시퀀스를 시작 제어 소프트웨어 인터페이스에서 &quot;시작 PC 벤팅&quot;버튼을 누름으로써 수행된다. 분위기 압력은 전면 액세스 도어를 당겨서 열고 챔버에 도달. </li><li> 열적 증발 한 쌍의 전극 사이에 텅스텐 증착 보트 (알루미나 코팅)을 탑재. 배치 1증발 보트에 G 비스무트 펠렛. </li><li> 마그네트론 스퍼터링 소스에 바나듐 스퍼터링 타겟을 탑재합니다. 스퍼터링 소스가 장착되지 않은 증착 시스템) 1.1.4 단계를 참조하십시오. </li><li> (선택, 스퍼터링 소스가 장착되지 않은 증착 시스템의 경우), 열 증착 한 쌍의 전극 사이에 텅스텐 증착 보트를 탑재. 증발 배에 0.5 g의 바나듐 슬러그를 놓습니다. </li><li> 증착 시스템의 전기 피드 스루에 폐쇄 루프 온도 컨트롤러 (온도 프로브 가열 / 냉각 전력이 두) 미니 바나나 커넥터를 연결합니다. </li></ol></li><li> 성장 기판의 제조 주 : 비스무트 나노 와이어의 형성은 선택 성장 기판에 민감하다. 유사한 결과는 유리 슬라이드, 규소 웨이퍼, 또는 금속 시트로부터 얻어졌다. 이는 기판이 증기 직전 세정한다 저자 추천증착 프로세스, 바나듐 하층의 일관된 접착력을 달성하기 위해서. 플라즈마 세정 및 습식 화학적 세정을 포함하는 다양한 기판 세정 기술은,인가 및 유사한 결과로 이어질 수있다. <ol><li> 산소 플라즈마에 의해 성장 기판 세정 <ol><li> 플라즈마 세정기로 성장 기판을 놓고 10 mTorr 이하의 그 기본 압력으로, 버튼 &quot;ON VAC&quot;을 누르면, 펌프 챔버. </li><li> 산소 가스 밸브를 열고 프론트 패널 버튼 &quot;ON GAS&quot;를 누름으로써 상기 챔버에 산소 가스를 도입하고 챔버 압력을 유지하는 &quot;INCR&quot;가스 유량 제어용 &quot;DECR&quot;버튼을 누름으로써 유량을 조정 약 100 mTorr로. </li><li> 전력 제어를위한 &quot;INCR&quot;및 &quot;DECR&quot;버튼을 눌러 20 W에 플라즈마 전력을 설정하고 버튼을 &quot;ON RF&quot;버튼에 의해 플라즈마를 점화. </li><li> 눌러 플라즈마를 끄기 전에 5 분 동안 기다립니다 &quot;; RF ON 블리드 &quot;버튼&quot;. 버튼을 눌러 챔버 벤트 &quot;및 기판을 검색한다. </li></ol></li><li> 습윤 화학적 방법에 의해 성장 기판 세정 <ol><li> 비이커에 함유 아세톤 성장 기판을 담그고. 초음파로 비커를 놓고 최대 전력에서 2 분 동안 초음파 처리. </li><li> 비커에서 기판을 제거하고 30 초 동안 세척 병에서 절대 알코올의 흐름과 함께 그들을 씻어. </li><li> 질소 가스 스트림에서 기판을 건조. </li></ol></li></ol></li><li> 기판 로딩 및 증착 시스템 펌핑 <ol><li> 기판 홀더에 기판 온도 제어 어셈블리 마운트. </li><li> 펠티어 쿨러 / 히터 어셈블리의 상단에 성장 기판을 장착하는 스프링 클립을 사용합니다. </li><li> 증착 원을 대향 기판으로, 증착 챔버 내로 완전히 조립 기판 홀더를 마운트. 에 전기 피드 스루 연결펠티에 쿨러 / 히터 조립체. </li><li> 기판에 의도하지 않은 증착을 방지하기 위해 기판 ​​셔터를 닫는다. </li><li> 증착 챔버를 펌핑 시작. 펌핑은 자동베이스 압력으로 챔버를 펌핑 시퀀스를 시작 제어 소프트웨어 인터페이스에 &quot;PC 펌핑 시작&quot;버튼을 누름으로써 수행된다. </li></ol></li></ol> 비스무트 나노 와이어의 성장 (2) 주 : 상기 증착 챔버의 기본 압력은 2 아래 × 10-6 토르에 도달 할 때까지 실험은 다음 단계로 이동되지 않는다. <ol><li> 바나듐 하층의 성막 주 : 바나듐 하층이 마그네트론 스퍼터링 방법에 의해 증착 될 때 최상의 실험 재현성이 달성된다. 스퍼터링 소스의 부재, 높은 재현성도 여전히 열 증착법을 이용하여 바나듐 하층을 증착함으로써 달성 될 수 있고, 증착 시스템이 제공 HASA 기저 압력 (≤ 5 × 10-7 토르). 자세한 내용은 3.1.2 단계를 참조하십시오. <ol><li> 마그네트론 스퍼터링 소스 바나듐 증착. <ol><li> 스퍼터링 소스에 아르곤 흐름을 시작합니다. 40 SCCM에 유량 설정. </li><li> 2.5 mTorr로의 챔버 압력 터보 분자 펌프의 회전 속도를 조정합니다. </li><li> 챔버는 서서히 정상 압력에 도달하면서, QCM에 두께 보정 계수를 설정한다. 바나듐, 밀도는 5.96 g / cm 3이고, Z-계수 0.530이다. </li><li> DC 스퍼터링 소스를 켜고 저자가 운영하는 증착 시스템의 경우 200-250 (W)의 전력을 설정, 증착 속도는이 전력에서 약 0.4 / 초이다. 기판 셔터를 개방하지 않고도, 2 분 동안 실행 소스를 유지한다. 주 : 바나듐 공급원에 자연 산화막이 신선한 바나듐 표면을 노출이 제거되는 단계를 통해. </li><li> 바나듐 depositio을 시작 기판 셔터를 엽니 다엔. 한편, 제로로 QCM의 누적 두께를 리셋. </li><li> 20 나노 미터의 겉보기 두께는 QCM 읽기 당 축적 될 때까지 침착을 계속합니다. 기판 셔터를 닫습니다. </li><li> 서서히 제로로 스퍼터 전력을 감소. 오프 소스를 켭니다. </li><li> 아르곤 흐름을 차단합니다. 그것의 전체 전력에 터보 분자 펌프를 돌려줍니다. </li></ol></li><li> 열 증착 원 바나듐 증착 (스퍼터링 소스가 장착되지 않은 증착 시스템, 선택적). <ol><li> 때문에 바나듐의 높은 융점 (1,910에 ° C)와 산화에 그 준비, 그것은 그것의 열 증발을 5 × 10-7 토르 이하의베이스 압력에서 실시하는 것이 권장된다. </li><li> QCM에 두께 보정 계수를 설정합니다. 바나듐, 밀도는 5.96 g / cm 3이고, Z-계수 0.530이다. </li><li> 바나듐 소스에 열 증발 전원을 켭니다.바나듐 슬러그가 녹아 때까지 천천히 텅스텐 보트에 난방 전력을 증가. </li><li> 기판 셔터가 닫혀으로 천천히 QCM 판독 당 이루어진다 2 Å / sec의 증착 속도까지 가열 전력을 증가시킨다. 바나듐 증착을 시작 기판 셔터를 엽니 다. 한편, 제로로 QCM의 누적 두께를 리셋. </li><li> 50 나노 미터의 명백한 두께가 축적 될 때까지 침착을 계속합니다. 기판 셔터를 닫습니다. </li><li> 서서히 제로로 열 증발 전력을 감소. 오프 소스를 켭니다. </li></ol></li></ol></li><li> 비스무트 나노 와이어의 증착 <ol><li> 상기 RT 또는 아래의 온도에서 증착을위한 비스무트, 온도 제어기에 원하는 값을 설정한다. 원하는 온도에 도달 할 때까지 기다립니다. </li><li> QCM에 두께 보정 계수를 설정합니다. 비스무트를 들어, 밀도는 9.78 g / cm 3이고, Z-계수 0.790이다. </li><li> 열 증발 전원 SU를 켭니다비스무트 소스에 pply. 천천히 QCM 판독 당 이루어진다 2 Å / sec의 증착율까지 텅스텐 보트로 가열 전력을 증가시킨다. </li><li> 비스무트 증착을 시작 기판 셔터를 엽니 다. 한편, 제로로 QCM의 누적 두께를 리셋. </li><li> 50 나노 미터의 명백한 두께가 축적 될 때까지 침착을 계속합니다. 기판 셔터를 닫습니다. </li><li> 서서히 제로로 열 증발 전력을 감소. 오프 소스를 켭니다. </li><li> 열 전기 냉각기 / 히터에 전원 공급 장치를 끄십시오. </li><li> 대기압에 증착 챔버와 벤트 챔버를 연다. 기판 홀더를 검색하고 비스무트 나노 와이어를 포함 기판을 수집합니다. </li></ol></li></ol>

<ol>
	<li>Hu, J. T., Odom, T. W., Lieber, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemistry+and+physics+in+one+dimension:+Synthesis+and+properties+of+nanowires+and+nanotubes.">Chemistry and physics in one dimension: Synthesis and properties of nanowires and nanotubes.</a> Acc. Chem. Res. 32, 435-445 (1999).</li><li>Akimov, A. V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+single+optical+plasmons+in+metallic+nanowires+coupled+to+quantum+dots.">Generation of single optical plasmons in metallic nanowires coupled to quantum dots.</a> Nature. 450, 402-406 (2007).</li><li>Thurn-Albrecht, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrahigh-density+nanowire+arrays+grown+in+self-assembled+diblock+copolymer+templates.">Ultrahigh-density nanowire arrays grown in self-assembled diblock copolymer templates.</a> Science. 290, 2126-2129 (2000).</li><li>Xia, Y. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One-dimensional+nanostructures:+Synthesis,+characterization,+and+applications.">One-dimensional nanostructures: Synthesis, characterization, and applications.</a> Adv. Mater. 15, 353-389 (2003).</li><li>Gudiksen, M. S., Lauhon, L. J., Wang, J., Smith, D. C., Lieber, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth+of+nanowire+superlattice+structures+for+nanoscale+photonics+and+electronics.">Growth of nanowire superlattice structures for nanoscale photonics and electronics.</a> Nature. 415, 617-620 (2002).</li><li>Yang, P. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled+growth+of+ZnO+nanowires+and+their+optical+properties.">Controlled growth of ZnO nanowires and their optical properties.</a> Adv. Funct. Mater. 12, 323-331 (2002).</li><li>Allen, J. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-resolution+detection+of+Au+catalyst+atoms+in+Si+nanowires.">High-resolution detection of Au catalyst atoms in Si nanowires.</a> Nature Nanotech. 3, 168-173 (2008).</li><li>Lin, Y. M., Sun, X. Z., Dresselhaus, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Theoretical+investigation+of+thermoelectric+transport+properties+of+cylindrical+Bi+nanowires.">Theoretical investigation of thermoelectric transport properties of cylindrical Bi nanowires.</a> Phys. Rev. B. 62, 4610-4623 (2000).</li><li>Isaacson, R. T., Williams, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alfv&#233;n-Wave+propagation+in+solid-state+plasmas.+III.+Quantum+oscillations+of+the+Fermi+surface+of+bismuth.">Alfv&#233;n-Wave propagation in solid-state plasmas. III. Quantum oscillations of the Fermi surface of bismuth.</a> Phys Rev. 185, 682-688 (1969).</li><li>Sandomirskii, V. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantum+size+effect+in+a+semimetal+film.">Quantum size effect in a semimetal film.</a> Sov. Phys. JETP. 25, 101-106 (1967).</li><li>Huber, T. E., Nikolaeva, A., Gitsu, D., Konopko, L., Graf, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantum+confinement+and+surface-state+effects+in+bismuth+nanowires.">Quantum confinement and surface-state effects in bismuth nanowires.</a> Physica E. 37, 194-199 (2007).</li><li>Black, M. R., Lin, Y. M., Cronin, S. B., Rabin, O., Dresselhaus, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Infrared+absorption+in+bismuth+nanowires+resulting+from+quantum+confinement.">Infrared absorption in bismuth nanowires resulting from quantum confinement.</a> Phys. Rev. B. 65, 2921-2930 (2002).</li><li>Hofmann, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+surfaces+of+bismuth:+Structural+and+electronic+properties.">The surfaces of bismuth: Structural and electronic properties.</a> Prog. Surf. Sci. 81, 191-245 (2006).</li><li>Huber, T. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Confinement+effects+and+surface-induced+charge+carriers+in+Bi+quantum+wires.">Confinement effects and surface-induced charge carriers in Bi quantum wires.</a> Appl Phys Lett. 84, 1326-1328 (2004).</li><li>Huber, T. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+state+band+mobility+and+thermopower+in+semiconducting+bismuth+nanowires.">Surface state band mobility and thermopower in semiconducting bismuth nanowires.</a> Phys. Rev. B. 83, 235414-23 (2011).</li><li>Dresselhaus, M. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> 23, 129-140 (2003).</li><li>Cheng, Y. -. T., Weiner, A. M., Wong, C. A., Balogh, M. P., Lukitsch, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress-induced+growth+of+bismuth+nanowires.">Stress-induced growth of bismuth nanowires.</a> Appl Phys Lett. 81, 3248-3250 (2002).</li><li>Volobuev, V. V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mechanism+of+Bi+nanowire+growth+from+Bi/Co+immiscible+composite+thin+films.">The mechanism of Bi nanowire growth from Bi/Co immiscible composite thin films.</a> J. Nanosci. Nanotech. 12, 8624-8629 (2012).</li><li>Shim, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On-film+formation+of+Bi+nanowires+with+extraordinary+electron+mobility.">On-film formation of Bi nanowires with extraordinary electron mobility.</a> Nano Lett. 9, 18-22 (2009).</li><li>Berglund, S. P., Rettie, A. J. E., Hoang, S., Mullins, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Incorporation+of+Mo+and+W+into+nanostructured+BiVO4+films+for+efficient+photoelectrochemical+water+oxidation.">Incorporation of Mo and W into nanostructured BiVO4 films for efficient photoelectrochemical water oxidation.</a> Phys. Chem. Chem. Phys. 14, 7065-7075 (2012).</li><li>Liu, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface-Energy+Induced+Formation+of+Single+Crystalline+Bismuth+Nanowires+over+Vanadium+Thin+Film+at+Room+Temperature.">Surface-Energy Induced Formation of Single Crystalline Bismuth Nanowires over Vanadium Thin Film at Room Temperature.</a> Nano Lett. 14, 5630-5635 (2014).</li></ol>

Authors have nothing to disclose.

비스무트 나노 와이어의 성장이 적어도 두 개의 증착 원, 바나듐 비스무트 용과 서로 물리적 기상 증착 시스템에서 수행되어야한다. 그것은 소스 중 하나는 바나듐의 증착을위한 마그네트론 스퍼터링 소스,하는 것이 좋습니다. 높은 진공 건조 스크롤 펌프에 의해 뒷받침 터보 분자 펌프에 의해 달성된다. 증착 시스템은 두께 시츄 모니터링에 대해 보정 한 수정 마이크로 저울 (QCM)을 갖추고...

나노 와이어는 하나의 차원에서 전하 캐리어 및 광자와 같은 다른 준 입자 및 플라즈몬의 전송을 제한. 따라서, 나노 와이어는 일반적으로 마이크로 / 나노 전자 공학, 포토닉스, 생물 의학, 환경 및 에너지 관련 기술의 응용 프로그램에 대해 그들에게 거의 무한한 가능성을 부여 소설, 전기, 자기 적, 광학적, 화학적 특성을 나타낸다. 1, 2를 지난 20 년 동안, 수많은 하향식 및 상향식 접근법 이러한 발전에도 불구하고 실험실 규모. 3-6 고품질의 금속 또는 반도체 나노 와이어의 광범위한 합성 개발되어, 각각의 접근법의 성공을위한 최종 제품의 특정한 고유 특성에 의존한다. 예를 들어, 인기있는 증기 - 액체 - 고체 (VLS) 방법은 나노 와이어의 합성에보다 높은 융점을 가지며, 촉매 &quot;종자&quot;대응 공융 합금을 형성한다. (7)을 따라서 반도체 물질에 더 적합특히 관심이 물질은 기존의 기술이 적용되지 않을 수 있습니다. 작은 간접 밴드 중첩 (0 K에서 -38 meV 인)와 유난히 빛을 전하 캐리어와 반 금속으로, 비스무트는 하나의 예이다. 벌크와 비교할 때 재료는 양자 구속이 좁은 밴드 갭 반도체에 비스무트 나노 와이어 또는 박막을 켤 수있다. 8-12 한편, 비스무트 형태의 표면을 준 이차원 금속 감소 차원에서 근본적으로 다른 동작 즉, 그것의 부피보다 훨씬 더 많은 금속이다. 13,14 그것은 비스무트의 표면이 2 × 10 4cm 2 V -1 초 -1의 전자 이동도를 실현하고 나노 와이어 형태의 화력에 강하게 기여하는 것으로 나타났다. 15을 이러한 전자 및 특정 열전 애플리케이션에서 비스무트 나노 와이어를 공부에 상당한 관심이있다. 12 ~ 16 그러나, 매우 낮은의 비스무트에 의한산화 융점 (544 K) 및 준비는, 높은 품질 및 기존의 증기 상 또는 용액 상 기술을 사용하여 단결정 비스무스 나노 와이어를 합성 할 과제로 남아. 이전에는 단일 결정 비스무트 나노 와이어 필름에 내장 된 스트레스의 출시에 기인한다 비스무트 박막의 진공 증착 동안 낮은 수율로 성장하는 몇 가지 그룹에 의해보고되었다. 17 ~ 20은 가장 최근에, 우리는 새로운 발견 고 진공하에 비스무트 열 증발에 기초하여 높은 수율로 단결정 비스무스 나노 와이어의 확장 형성을 유도되는 방법. (21) 이전에 비교하여이 방법을보고,이 기술의 가장 독특한 특징은 성장 기판은 갓 코팅 있다는 증착 이전에 비스무트 바나듐 나노 다공성 박막과. 후자의 열 증발하는 동안, 비스무트 증기는 밴의 나노 다공성 구조로 침투에이디 엄 필름과는 nanodomains 거기 응축. 바나듐 축합 비스무트 의해 습윤되지 않기 때문에, 함침 도메인은 계속해서 그 표면 에너지를 방출 바나듐 행렬로부터 expulsed된다. 그것은 수직 비스무트 나노 와이어를 형성 비스무트 nanodomains 제명의 연속이다. 비스무트 도메인 직경의 1-2 나노 미터이기 때문에, 그들은 실온에서 그들을 거의 용융 만드는 중요한 융점 억제 될 수 있습니다. 그 결과, 나노 와이어 성장은 RT 유지 기판과 진행한다. 한편, 비스무트 도메인의 이동이 열적으로 활성화 된 바와 같이, 나노 와이어의 길이 및 폭은 단순히 성장 기판의 온도를 조절함으로써 넓은 범위에 걸쳐 조정될 수있다. 상세한 프로토콜은 비디오 필드에 새로운 실무자 고진공, 산소가없는 환경에서 박막의 물리적 증착과 관련된 다양한 일반적인 문제를 방지하기위한 것이다.

<table><tbody><tr><td>Bismuth</td><td>Sigma-Aldrich</td><td>556130</td><td>Granular, 99.999%</td></tr><tr><td>Vanadium Slug</td><td>Alfa Aesar</td><td>42829</td><td>3.175&amp;nbsp;mm (0.125&amp;nbsp;in) dia x 6.35&amp;nbsp;mm (0.25&amp;nbsp;in) length, 99.8%</td></tr><tr><td>Vanadium Sputtering Target</td><td>Kurt J. Lesker</td><td>EJTVXXX253A2</td><td>3.00&quot; Dia. x 0.125&quot; Thick, 99.5%</td></tr><tr><td>Acetone</td><td>Sigma-Aldrich</td><td>179124</td><td>&gt;99.5%</td></tr><tr><td>Ethanol</td><td>Alfa Aesar</td><td>33361</td><td>Anhydrous</td></tr><tr><td>Silicon Wafer</td><td>University Wafers</td><td></td><td>300 microns in thickness, (100) orientation</td></tr><tr><td>Silver Filled Epoxy</td><td>Circuit Works</td><td>CW2400</td><td>Two part conductive epoxy resin</td></tr><tr><td>Tungsten Boat, Alumina Coated</td><td>R. D. Mathis</td><td>S9B-AO-W</td><td>For bismuth thermal evaporation</td></tr><tr><td>Tungsten Boat</td><td>R. D. Mathis</td><td>S4-.015W</td><td>For vanadium thermal evaporation</td></tr><tr><td>RIE Plasma</td><td>Nordson March</td><td>CS-1701</td><td></td></tr><tr><td>PVD 75 Vapor Deposition Platform</td><td>Kurt J. Lesker</td><td>PEDP75FTCLT001</td><td>Equipped with three thermal evaporation source and one DC magnetron sputtering source</td></tr><tr><td>Thermoelectric Temperature Controller</td><td>LairdTech</td><td>MTTC-1410</td><td></td></tr><tr><td>PT1000 RGD</td><td>LairdTech</td><td>340912-01</td><td>Temperature sensor for MTTC-1410</td></tr><tr><td>Thermoelectric Module</td><td>LairdTech</td><td>56910-502</td><td></td></tr><tr><td>Ultrasonicator</td><td>Crest Ultrasonics</td><td>Tru-Sweep 175</td><td></td></tr></tbody></table>

seedless growth of bismuth nanowire array via vacuum thermal evaporation

여기 씨앗 및 템플릿이없는 기술은 RT에서 고진공에서 열적 증발, 비스무트 나노 와이어를 성장하기 위해 스케일 러블 설명된다. 종래에 금속 박막, 열 증발 증착물의 제조에 비스무트 갓 마그네트론 스퍼터링 또는 열 증발에 의해 증착된다 RT 유지 바나듐 평면 박막 위에 수직 단결정 나노 와이어의 배열로 보유. 성장 기판의 온도를 제어함으로써, 나노 와이어의 길이 및 폭이 넓은 범위를 통해 조정될 수있다. 이 새로운 기술에 대한 책임 이전에 알려지지 않은 나노 와이어 성장 메커니즘입니다 바나듐 박막의 가벼운 다공성의 뿌리. 바나듐 기공에 함침, 비스무트 도메인 (~ 1 nm의)은 그 융점이 억제 과도한 표면 에너지를 가지고 연속적으로 나노 와이어를 형성하기 위해 바나듐 행렬에서 그들을 배출한다. 이 발견은 확장 기상 신디의 타당성을 보여고순도 ESIS는 촉매를 사용하지 않고 나노 물질.

마그네트론 스퍼터링, 열 증착 방법에 의해 형성된 바나듐 하층의 단면 SEM 이미지는 그림 2. 주사 전자 현미경 (SEM) 이미지는 다른 기판 온도에서 형성 비스무트 나노 와이어 (도 3)에 대해 제공되게된다. 비스무트 나노 와이어의 결정 구조는 투과형 전자 현미경 (TEM), 선택 영역 전자 회절 (SAED) 및 X 선 회절 (XRD) 연구 (도 4)를 통해 결정된다. 에너지 분산 형 X 선...

Watch this Scientific Journal Video about Seedless Growth of Bismuth Nanowire Array via Vacuum Thermal Evaporation at JoVE.com

Seedless Growth of Bismuth Nanowire Array via Vacuum Thermal Evaporation

A protocol for seedless and high yield growth of bismuth nanowire arrays through vacuum thermal evaporation technique is presented.

진공 열 증발을 통해 비스무트 나노 와이어 어레이의 씨앗 성장

Here a seedless and template-free technique is demonstrated to scalably grow bismuth nanowires, through thermal evaporation in high vacuum at RT. ...

seedless-growth-bismuth-nanowire-array-via-vacuum-thermal

Universidad San Sebastian

Research

JoVE Journal

Engineering

8.3K 조회수.  Brookhaven National Laboratory. A protocol for seedless and high yield growth of bismuth nanowire arrays through vacuum thermal evaporation technique is presented. 

비디오: Seedless Growth of Bismuth Nanowire Array via Vacuum Thermal Evaporation

Fabrication, Densification, and Replica Molding of 3D Carbon Nanotube Microstructures

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques 1, 2, and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. 
Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT microstructures, significantly increases the packing density of CNTs. This process enables directed transformation of vertical CNT microstructures into straight, inclined, and twisted shapes, which have robust mechanical properties exceeding those of typical microfabrication polymers. This in turn enables formation of nanocomposite CNT master molds by capillary-driven infiltration of polymers. The replica structures exhibit the anisotropic nanoscale texture of the aligned CNTs, and can have walls with sub-micron thickness and aspect ratios exceeding 50:1. Integration of CNT microstructures in fabrication offers further opportunity to exploit the electrical and thermal properties of CNTs, and diverse capabilities for chemical and biochemical functionalization 3.

We present methods for fabrication of patterned microstructures of vertically aligned carbon nanotubes (CNTs), and their use as master molds for production of polymer microstructures with organized nanoscale surface texture. The CNT forests are densified by condensation of solvent onto the substrate, which significantly increases their packing density and enables self-directed formation of 3D shapes.

3D 카본 나노튜브 Microstructures의 제조, Densification 및 복제 성형

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip ...

연구

공학

Dry Oxidation and Vacuum Annealing Treatments for Tuning the Wetting Properties of Carbon Nanotube Arrays

In this article, we describe a simple method to reversibly tune the wetting properties of vertically aligned carbon nanotube (CNT) arrays. Here, CNT arrays are defined as densely packed multi-walled carbon nanotubes oriented perpendicular to the growth substrate as a result of a growth process by the standard thermal chemical vapor deposition (CVD) technique.1,2 These CNT arrays are then exposed to vacuum annealing treatment to make them more hydrophobic or to dry oxidation treatment to render them more hydrophilic. The hydrophobic CNT arrays can be turned hydrophilic by exposing them to dry oxidation treatment, while the hydrophilic CNT arrays can be turned hydrophobic by exposing them to vacuum annealing treatment. Using a combination of both treatments, CNT arrays can be repeatedly switched between hydrophilic and hydrophobic.2 Therefore, such combination show a very high potential in many industrial and consumer applications, including drug delivery system and high power density supercapacitors.3-5
The key to vary the wettability of CNT arrays is to control the surface concentration of oxygen adsorbates. Basically oxygen adsorbates can be introduced by exposing the CNT arrays to any oxidation treatment. Here we use dry oxidation treatments, such as oxygen plasma and UV/ozone, to functionalize the surface of CNT with oxygenated functional groups. These oxygenated functional groups allow hydrogen bond between the surface of CNT and water molecules to form, rendering the CNT hydrophilic. To turn them hydrophobic, adsorbed oxygen must be removed from the surface of CNT. Here we employ vacuum annealing treatment to induce oxygen desorption process. CNT arrays with extremely low surface concentration of oxygen adsorbates exhibit a superhydrophobic behavior.

This article describes a simple method to fabricate vertically aligned carbon nanotube arrays by CVD and to subsequently tune their wetting properties by exposing them to vacuum annealing or dry oxidation treatment.

탄소 나노 튜브 배열의 으러 속성을 조정을위한 트리트먼트 소둔 건식 산화, 진공

In this article, we describe a simple method to reversibly  tune the wetting properties of vertically aligned carbon nanotube (CNT) arrays.  Here, CNT ...

Ultrahigh Density Array of Vertically Aligned Small-molecular Organic Nanowires on Arbitrary Substrates

In recent years &pi;-conjugated organic semiconductors have emerged as the active material in a number of diverse applications including large-area, low-cost displays, photovoltaics, printable and flexible electronics and organic spin valves. Organics allow (a) low-cost, low-temperature processing and (b) molecular-level design of electronic, optical and spin transport characteristics. Such features are not readily available for mainstream inorganic semiconductors, which have enabled organics to carve a niche in the silicon-dominated electronics market. The first generation of organic-based devices has focused on thin film geometries, grown by physical vapor deposition or solution processing. However, it has been realized that organic nanostructures can be used to enhance performance of above-mentioned applications and significant effort has been invested in exploring methods for organic nanostructure fabrication.	
A particularly interesting class of organic nanostructures is the one in which vertically oriented organic nanowires, nanorods or nanotubes are organized in a well-regimented, high-density array. Such structures are highly versatile and are ideal morphological architectures for various applications such as chemical sensors, split-dipole nanoantennas, photovoltaic devices with radially heterostructured "core-shell" nanowires, and memory devices with a cross-point geometry. Such architecture is generally realized by a template-directed approach. In the past this method has been used to grow metal and inorganic semiconductor nanowire arrays. More recently &pi;-conjugated polymer nanowires have been grown within nanoporous templates. However, these approaches have had limited success in growing nanowires of technologically important &pi;-conjugated small molecular weight organics, such as tris-8-hydroxyquinoline aluminum (Alq3), rubrene and methanofullerenes, which are commonly used in diverse areas including organic displays, photovoltaics, thin film transistors and spintronics.	
Recently we have been able to address the above-mentioned issue by employing a novel "centrifugation-assisted" approach. This method therefore broadens the spectrum of organic materials that can be patterned in a vertically ordered nanowire array. Due to the technological importance of Alq3, rubrene and methanofullerenes, our method can be used to explore how the nanostructuring of these materials affects the performance of aforementioned organic devices. The purpose of this article is to describe the technical details of the above-mentioned protocol, demonstrate how this process can be extended to grow small-molecular organic nanowires on arbitrary substrates and finally, to discuss the critical steps, limitations, possible modifications, trouble-shooting and future applications.

We report a simple method for fabricating an ultrahigh density array of vertically ordered small-molecular organic nanowires. This method allows for synthesis of complex heterostructured hybrid nanowire geometries, which can be inexpensively grown on arbitrary substrates. These structures have potential applications in organic electronics, optoelectronics, chemical sensing, photovoltaics and spintronics.

임의 기판에 수직으로 정렬 작은 분자 유기 나노 와이어의 초 밀도 배열

In  recent years &pi;-conjugated  organic semiconductors have emerged as the active material in a number of  diverse applications including large-area, ...

Analysis of Contact Interfaces for Single GaN Nanowire Devices

Single GaN nanowire (NW) devices fabricated on SiO2 can exhibit a strong degradation after annealing due to the occurrence of void formation at the contact/SiO2 interface. This void formation can cause cracking and delamination of the metal film, which can increase the resistance or lead to a complete failure of the NW device. In order to address issues associated with void formation, a technique was developed that removes Ni/Au contact metal films from the substrates to allow for the examination and characterization of the contact/substrate and contact/NW interfaces of single GaN NW devices. This procedure determines the degree of adhesion of the contact films to the substrate and NWs and allows for the characterization of the morphology and composition of the contact interface with the substrate and nanowires. This technique is also useful for assessing the amount of residual contamination that remains from the NW suspension and from photolithographic processes on the NW-SiO2 surface prior to metal deposition. The detailed steps of this procedure are presented for the removal of annealed Ni/Au contacts to Mg-doped GaN NWs on a SiO2 substrate.

A technique was developed that removes Ni/Au contact metal films from their substrate to allow for the examination and characterization of the contact/substrate and contact/NW interfaces of single GaN nanowire devices.

단 하나의 GaN 나노 와이어 장치에 대한 문의 인터페이스의 분석

Single GaN nanowire (NW) devices fabricated on SiO2 can exhibit  a strong degradation after annealing due to the  occurrence of void formation at the ...

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

Monolayer Contact Doping (MLCD) is a simple method for doping of surfaces and nanostructures1. MLCD results in the formation of highly controlled, ultra shallow and sharp doping profiles at the nanometer scale. In MLCD process the dopant source is a monolayer containing dopant atoms.
In this article a detailed procedure for surface doping of silicon substrate as well as silicon nanowires is demonstrated. Phosphorus dopant source was formed using tetraethyl methylenediphosphonate monolayer on a silicon substrate. This monolayer containing substrate was brought to contact with a pristine intrinsic silicon target substrate and annealed while in contact. Sheet resistance of the target substrate was measured using 4 point probe. Intrinsic silicon nanowires were synthesized by chemical vapor deposition (CVD) process using a vapor-liquid-solid (VLS) mechanism; gold nanoparticles were used as catalyst for nanowire growth. The nanowires were suspended in ethanol by mild sonication. This suspension was used to dropcast the nanowires on silicon substrate with a silicon nitride dielectric top layer. These nanowires were doped with phosphorus in similar manner as used for the intrinsic silicon wafer. Standard photolithography process was used to fabricate metal electrodes for the formation of nanowire based field effect transistor (NW-FET). The electrical properties of a representative nanowire device were measured by a semiconductor device analyzer and a probe station.

A detailed procedure for surface doping of Silicon interfaces is provided. The ultra-shallow surface doping is demonstrated by using phosphorus containing monolayers and rapid annealing process. The method can be used for doping of macroscopic area surfaces as well as nanostructures.

유기 화합물을 사용하여 실리콘 표면과 나노 와이어의 단층 연락 도핑

Monolayer Contact Doping (MLCD) is a simple method for doping of surfaces and nanostructures1. MLCD results in the formation of highly controlled, ultra ...

Atomically Defined Templates for Epitaxial Growth of Complex Oxide Thin Films

Atomically defined substrate surfaces are prerequisite for the epitaxial growth of complex oxide thin films. In this protocol, two approaches to obtain such surfaces are described. The first approach is the preparation of single terminated perovskite SrTiO3 (001) and DyScO3 (110) substrates. Wet etching was used to selectively remove one of the two possible surface terminations, while an annealing step was used to increase the smoothness of the surface. The resulting single terminated surfaces allow for the heteroepitaxial growth of perovskite oxide thin films with high crystalline quality and well-defined interfaces between substrate and film. In the second approach, seed layers for epitaxial film growth on arbitrary substrates were created by Langmuir-Blodgett (LB) deposition of nanosheets. As model system Ca2Nb3O10- nanosheets were used, prepared by delamination of their layered parent compound HCa2Nb3O10. A key advantage of creating seed layers with nanosheets is that relatively expensive and size-limited single crystalline substrates can be replaced by virtually any substrate material.

Various procedures are outlined to prepare atomically defined templates for epitaxial growth of complex oxide thin films. Chemical treatments of single crystalline SrTiO3 (001) and DyScO3 (110) substrates were performed to obtain atomically smooth, single terminated surfaces. Ca2 Nb3 O10- nanosheets were used to create atomically defined templates on arbitrary substrates.

복합 산화물 박막의 에피 택셜 성장을위한 원자 적으로 정의 된 템플릿

Atomically defined substrate surfaces are prerequisite for the epitaxial growth of complex oxide thin films. In this protocol, two approaches to obtain ...

화학

Fabrication of Carbon Nanotube High-Frequency Nanoelectronic Biosensor for Sensing in High Ionic Strength Solutions

The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) 1-4 make them good candidates for high sensitivity biosensors. When a charged molecule binds to such a sensor surface, it alters the carrier density5 in the sensor, resulting in changes in its DC conductance. However, in an ionic solution a charged surface also attracts counter-ions from the solution, forming an electrical double layer (EDL). This EDL effectively screens off the charge, and in physiologically relevant conditions ~100 millimolar (mM), the characteristic charge screening length (Debye length) is less than a nanometer (nm). Thus, in high ionic strength solutions, charge based (DC) detection is fundamentally impeded6-8.
We overcome charge screening effects by detecting molecular dipoles rather than charges at high frequency, by operating carbon nanotube field effect transistors as high frequency mixers9-11. At high frequencies, the AC drive force can no longer overcome the solution drag and the ions in solution do not have sufficient time to form the EDL. Further, frequency mixing technique allows us to operate at frequencies high enough to overcome ionic screening, and yet detect the sensing signals at lower frequencies11-12. Also, the high transconductance of SWNT transistors provides an internal gain for the sensing signal, which obviates the need for external signal amplifier.
Here, we describe the protocol to (a) fabricate SWNT transistors, (b) functionalize biomolecules to the nanotube13, (c) design and stamp a poly-dimethylsiloxane (PDMS) micro-fluidic chamber14 onto the device, and (d) carry out high frequency sensing in different ionic strength solutions11.

We describe the device fabrication and measurement protocol for carbon nanotube based high frequency biosensors. The high frequency sensing technique mitigates the fundamental ionic (Debye) screening effect and allows nanotube biosensor to be operated in high ionic strength solutions where conventional electronic biosensors fail. Our technology provides a unique platform for point-of-care (POC) electronic biosensors operating in physiologically relevant conditions.

높은 이온 강도 솔루션에 감지하기위한 탄소 나노 튜브 고주파 나노 바이오 센서의 제작

The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) 1-4 make them ...

생체공학

Synthesis of Substrate-Bound Au Nanowires Via an Active Surface Growth Mechanism

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a challenge, as it requires asymmetric growth of symmetric crystals. Here, we report a distinctive synthesis of substrate-bound Au nanowires. This template-free synthesis employs thiolated ligands and substrate adsorption to achieve the continuous asymmetric deposition of Au in solution at ambient conditions. The thiolated ligand prevented the Au deposition on the exposed surface of the seeds, so the Au deposition only occurs at the interface between the Au seeds and the substrate. The side of the newly deposited Au nanowires is immediately covered with the thiolated ligand, while the bottom facing the substrate remains ligand-free and active for the next round of Au deposition. We further demonstrate that this Au nanowire growth can be induced on various substrates, and different thiolated ligands can be used to regulate the surface chemistry of the nanowires. The diameter of the nanowires can also be controlled with mixed ligands, in which another &#34;bad&#34; ligand could turn on the lateral growth. With the understanding of the mechanism, Au nanowire-based nanostructures can be designed and synthesized.

We report a solution-based method to synthesize substrate-bound Au nanowires. By tuning the molecular ligands used during the synthesis, the Au nanowires can be grown from various substrates with different surface properties. Au nanowire-based nanostructures can also be synthesized by adjusting the reaction parameters.

활성 표면 성장 메커니즘을 통해 기판 바인딩된 Au 나노 와이어의 합성

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a ...

A Standard and Reliable Method to Fabricate Two-Dimensional Nanoelectronics

Two-dimensional (2D) materials have attracted huge attention due to their unique properties and potential applications. Since wafer scale synthesis of 2D materials is still in nascent stages, scientists cannot fully rely on traditional semiconductor techniques for related research. Delicate processes from locating the materials to electrode definition need to be well controlled. In this article, a universal fabrication protocol required in manufacturing nanoscale electronics, such as 2D quasi-heterojunction bipolar transistors (Q-HBT), and 2D back-gated transistors are demonstrated. This protocol includes the determination of material position, electron beam lithography (EBL), metal electrode definition, et al. A step by step narrative of the fabrication procedures for these devices are also presented. Furthermore, results show that each of the fabricated devices has achieved high performance with high repeatability. This work reveals a comprehensive description of process flow for preparing 2D nano-electronics, enables the research groups to access this information, and pave the way toward future electronics.

The article aims to introduce a standard and reliable fabrication procedure for the development of future low dimensional nanoelectronics.

2 차원 일렉트로닉스를 조작 하는 표준 및 신뢰할 수 있는 방법

Two-dimensional (2D) materials have attracted huge attention due to their unique properties and potential applications. Since wafer scale synthesis of 2D ...

Fabrication of Schottky Diodes on Zn-polar BeMgZnO/ZnO Heterostructure Grown by Plasma-assisted Molecular Beam Epitaxy

Heterostructure field effect transistors (HFETs) utilizing a two dimensional electron gas (2DEG) channel have a great potential for high speed device applications. Zinc oxide (ZnO), a semiconductor with a wide bandgap (3.4 eV) and high electron saturation velocity has gained a great deal of attention as an attractive material for high speed devices. Efficient gate modulation, however, requires high-quality Schottky contacts on the barrier layer. In this article, we present our Schottky diode fabrication procedure on Zn-polar BeMgZnO/ZnO heterostructure with high density 2DEG which is achieved through strain modulation and incorporation of a few percent Be into the MgZnO-based barrier during growth by molecular beam epitaxy (MBE). To achieve high crystalline quality, nearly lattice-matched high-resistivity GaN templates grown by metal-organic chemical vapor deposition (MOCVD) are used as the substrate for the subsequent MBE growth of the oxide layers. To obtain the requisite Zn-polarity, careful surface treatment of GaN templates and control over the VI/II ratio during the growth of low temperature ZnO nucleation layer are utilized. Ti/Au electrodes serve as Ohmic contacts, and Ag electrodes deposited on the O2 plasma pretreated BeMgZnO surface are used for Schottky contacts.

Attainment of high-quality Schottky contacts is imperative for achieving efficient gate modulation in heterostructure field effect transistors (HFETs). We present the fabrication methodology and characteristics of Schottky diodes on Zn-polar BeMgZnO/ZnO heterostructures with high-density two dimensional electron gas (2DEG), grown by plasma-assisted molecular beam epitaxy on GaN templates.

Heterostructure field effect transistors (HFETs) utilizing a two dimensional electron gas (2DEG) channel have a great potential for high speed device ...