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.

注意：使用する前に、関連するすべての物質安全データシート（MSDS）を参照してください。ナノ材料は、そのバルク対応物に比べて付加的な危険性を有していてもよいです。工学的制御（ヒュームフード）と個人用保護具の使用を含む、ナノ材料で覆われた基板を取り扱うときは、すべての適切な安全対策を使用してください（安全メガネ、手袋、白衣、完全長ズボン、靴、つま先を閉じました）。 1.準備作業<ol><li>蒸着システムの調製<ol><li>大気圧に堆積チャンバをベントし、チャンバを開きます。通気は、自動的に大気圧にベント室シーケンスを開始する制御ソフトウェアインタフェースの「スタートPCベント」ボタンを押すことによって行われます。大気圧に達するとフロントアクセスドアを引いて、チャンバーを開きます。 </li><li>熱蒸着、一対の電極間にタングステン蒸着ボート（アルミナコーティングされた）をマウントします。場所1蒸着ボートにペレットビスマスグラム。 </li><li>マグネトロンスパッタ源にバナジウムスパッタリングターゲットをマウントします。スパッタ源を搭載していない堆積システムのための）1.1.4のステップを参照してください。 </li><li> （オプション、スパッタ源が装備されていない堆積システムのための ）熱蒸着、一対の電極間にタングステン蒸着用ボートをマウントします。蒸発ボートに0.5グラムのバナジウムスラグを置きます。 </li><li>堆積システムの電気フィードスルーに閉ループ温度コントローラの（温度プローブの加熱/冷却能力のための2つおよび2）のミニバナナコネクタを接続します。 </li></ol></li><li>成長基板の調製 注意：ビスマスナノワイヤーの形成は選択の成長基板の影響を受けません。同様の結果は、スライドガラス、シリコンウエハ、または金属薄板から得られました。これは、基板は、蒸気の直前に洗浄しなければならない著者によって推奨されます堆積プロセス、バナジウム下層の一貫した接着を達成するために。プラズマ洗浄及び湿式化学洗浄を含む様々な基板洗浄技術は、適用され、同様の結果をもたらすことができます。 <ol><li>酸素プラズマによる成長基板を洗浄<ol><li>プラズマクリーナーに成長基板を配置し、10ミリトールのそのベース圧力に、ボタン「ON VAC &quot;を押すことにより、チャンバーをポンプ。 </li><li>酸素ガスのバルブを開いて、前面パネルのボタンを「ON GAS」を押すと、チャンバに酸素ガスを導入し、チャンバ圧を維持するために、「INCR」とガス流量制御のための「DECR」ボタンを押すことにより、流量を調節約100ミリトール。 </li><li>電力制御のために「INCR」と「DECR」ボタンを押して、20 Wのプラズマパワーを設定し、ボタンを「ON RF」を押すことでプラズマを点火。 </li><li>押して、プラズマをオフにする前に5分間待ってください」; RF ON BLEED「ボタン」ボタンを押すことによって、チャンバをベント」と、基板を取り出します。 </li></ol></li><li>湿式化学法による成長基板を洗浄<ol><li>ビーカーに入れたアセトンの成長基板を浸し。超音波装置にビーカーを置き、最大電力で2分間超音波処理します。 </li><li>ビーカーから基板を取り外し、30秒間洗浄瓶から無水アルコールのストリームでそれらをすすぎます。 </li><li>窒素ガス流に基板を乾燥させます。 </li></ol></li></ol></li><li>基板ローディングと堆積システムのポンプ<ol><li>基板ホルダに基板温度制御アセンブリを取り付けます。 </li><li>ペルチェクーラー/ヒーターアセンブリの上に成長基板を取り付けるためにスプリングクリップを使用してください。 </li><li>蒸着源に面する基板と、蒸着チャンバー内に完全に組み立てられた基板ホルダーを取り付けます。に電気的フィードスルーを接続しますペルチェクーラー/ヒーターアセンブリ。 </li><li>基板に意図しない堆積を回避するために、基板シャッターを閉じます。 </li><li>堆積チャンバをポンプダウンを開始します。ポンプは自動的にベース圧力までチャンバをポンピングシーケンスを開始する制御ソフトウェアインタフェースの「PCのポンピングを開始」ボタンを押すことによって行われます。 </li></ol></li></ol>ビスマスナノワイヤーの成長2。 注：堆積チャンバーのベース圧は、以下の2×10 -6 Torr以下になるまでの実験は、次のステップに移動していません。 <ol><li>バナジウム下地層の堆積 注：バナジウム下地層をマグネトロンスパッタリング法により成膜されたときに最高の実験の再現性が達成されます。スパッタリング源の不存在下で、高い再現性も依然として熱蒸発法を使用して、バナジウム下地層を堆積させることによって達成することができ、その堆積システムヘクタールを提供SA低いベース圧力（≤5×10 -7トル）。詳細については、3.1.2のステップを参照してください。 <ol><li>マグネトロンスパッタ源とバナジウム堆積。 <ol><li>スパッタ源にアルゴンの流れを開始します。 40 SCCMに設定流量。 </li><li> 2.5ミリトールのチャンバ圧力のためのターボ分子ポンプの回転速度を調整します。 </li><li>チャンバーは徐々に定常状態の圧力に達している間、QCMの厚さの校正係数を設定します。バナジウムの場合、密度は5.96グラム/ cm 3であり、Z-ファクターは0.530です。 </li><li> DCスパッタ源をオンにして、著者が運営する堆積システムの場合200〜250 W.の電力を設定し、堆積速度は、この電力で約0.4オングストローム/秒です。基板シャッターを開くことなく、2分間実行しているソースを保持します。 注：この工程によりバナジウム源の自然酸化が新鮮なバナジウム表面を露出、削除されます。 </li><li>バナジウムを開始するために、基板シャッターを開きdepositioN。一方で、ゼロにQCMの累積厚さをリセットします。 </li><li> 20nmの見かけの厚さは、QCMの読み取りごとに、蓄積されるまでの堆積を続けます。基板シャッターを閉じます。 </li><li>徐々にゼロにスパッタ電力を下げます。ソースをオフにします。 </li><li>アルゴンの流れを遮断します。そのフルパワーにターボ分子ポンプを返します。 </li></ol></li><li>熱蒸発源とバナジウム堆積（ スパッタ源が装備されていない堆積システムのために、オプション）。 <ol><li>バナジウムの高融点（1910へ ℃）と酸化への準備は、それは、その熱蒸着は5×10 -7 Torr以下のベース圧力で実施されることをお勧めします。 </li><li> QCMの厚さの校正係数を設定します。バナジウムの場合、密度は5.96グラム/ cm 3であり、Z-ファクターは0.530です。 </li><li>バナジウム源に熱蒸着電源をオンにしてください。バナジウムスラグが溶融するまでゆっくりとタングステンボートに加熱電力を増加させます。 </li><li>基板シャッターが閉じたままで2オングストローム/秒の蒸着速度がQCM読み取り当たり、達成されるまで、ゆっくりと加熱力を増加させます。バナジウム堆積を開始するために、基板シャッターを開きます。一方で、ゼロにQCMの累積厚さをリセットします。 </li><li> 50nmの見かけ厚さが蓄積されるまで、堆積を続けます。基板シャッターを閉じます。 </li><li>徐々にゼロに熱蒸着電力を下げます。ソースをオフにします。 </li></ol></li></ol></li><li>ビスマスナノワイヤーの堆積<ol><li> RT上または下の温度でビスマス堆積のために、温度コントローラに必要な値を設定します。所望の温度に達するまで待ちます。 </li><li> QCMの厚さの校正係数を設定します。ビスマスの場合、密度は9.78グラム/ cm 3であり、Z-ファクターは0.790です。 </li><li>熱蒸着パワーのsuをオンにしビスマスソースにpply。 2オングストローム/秒の蒸着速度がQCM読み取り当たり、達成されるまで徐々にタングステンボートに加熱電力を増大させます。 </li><li>ビスマス堆積を開始するために、基板シャッターを開きます。一方で、ゼロにQCMの累積厚さをリセットします。 </li><li> 50nmの見かけ厚さが蓄積されるまで、堆積を続けます。基板シャッターを閉じます。 </li><li>徐々にゼロに熱蒸着電力を下げます。ソースをオフにします。 </li><li>熱電冷却器/加熱器の電源をオフにします。 </li><li>大気圧に堆積チャンバをベントし、チャンバを開きます。基板ホルダーを取得し、基板をカバービスマスナノワイヤを集めます。 </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.

ビスマスのナノワイヤの成長は、少なくとも二つの蒸着源、ビスマス及びバナジウムのために別のものとの物理的蒸着装置で実施されます。これは、情報源の一つは、バナジウムの堆積のために、マグネトロンスパッタリング源であることをお勧めします。高真空は、ドライスクロールポンプによって裏打ちされたターボ分子ポンプによって達成されます。蒸着システムは、 その場での</...

ナノワイヤは、1つの次元での光子とプラズモンとして、電荷キャリアと他の準粒子の輸送を閉じ込めます。したがって、ナノワイヤは、通常のマイクロ/ナノエレクトロニクス、フォトニクス、生物医学、環境・エネルギー関連技術のアプリケーションのためにそれらをほぼ無限の可能性を付与小説、電気的、磁気的、光学的および化学的特性を示す。1,2を過去20年の間に、多数トップダウンおよびボトムアップのアプローチは、実験室規模で高品質の金属または半導体ナノワイヤの広い範囲を合成するために開発された。3-6これらの開発にもかかわらず、それぞれのアプローチは、成功のための最終製品の特定のユニークな特性に依存しています。例えば、人気のある気相-液相-固相（VLS）メソッドは、より高い融点を有し、対応する触媒の「シード」と共晶合金を形成する半導体材料のためのより良い適合である。7この結果、ナノワイヤーの合成特に関心のある材料は、既存の技術でカバーされない場合があります。 小さな間接バンドの重なり（0 Kにおける-38 meVで）と異常光電荷キャリアを持つ半金属としては、ビスマスはその一例です。そのバルクと比較した場合、量子閉じ込めが狭いバンドギャップ半導体にビスマスナノワイヤまたは薄膜を回すことができるような材料は、減少した寸法で、根本的に異なる動作をします。一方8-12、ビスマス形の表面準二次元金属それは、その大部分よりもはるかに多くの金属である。13,14これは、ビスマスの表面は、2×10 4 cm 2のV -1 秒 -1の電子移動度を達成し、ナノワイヤの形で、その熱電電力に強く寄与していることが示された。15のようにこのような、電子特に熱電アプリケーションにおけるビスマスナノワイヤを研究に大きな関心があります。12-16しかし、ビスマスの非常に低いのために融点（544 K）及び酸化のための準備は、高品質で、伝統的な気相または液相技術を用いて単結晶ビスマスのナノワイヤを合成するための課題です。 これまでは、単結晶ビスマスナノワイヤがフィルムに組み込まれたストレスの解放に起因しているビスマス薄膜の真空蒸着時に低い収率で成長することをいくつかのグループにより報告されている。17-20は最近、我々は小説を発見しました高真空下でビスマスの熱蒸着に基づいており、高い収率で単結晶ビスマスナノワイヤーのスケーラブルな形成につながる技術。21以前に報告された方法と比較すると、この技術の最もユニークな特徴は、成長基板が新鮮に被覆されていることですナノ多孔性バナジウムの薄い層を有するビスマス堆積前。後者の熱蒸着の間に、ビスマス蒸気はバンのナノ多孔性構造に浸透Adiumのフィルムとナノドメインとしてそこに凝縮。バナジウムは、凝縮ビスマスで濡れていないので、浸潤領域は、その後、その表面エネルギーを解放するためにバナジウムマトリックスからexpulsedされます。これは、垂直ビスマスナノワイヤーを形成ビスマスナノドメインの連続追放です。ビスマスドメインは直径のわずか1〜2 nmであるので、RTでそれらをほぼ溶融させる重要な融点抑制、の対象となっています。その結果、ナノワイヤの成長は室温で保持された基板に進みます。一方、ビスマスドメインの移行が、熱的に活性化されると、ナノワイヤの長さと幅は、単純に、成長基板の温度を制御することによって、広い範囲にわたって調整することができます。この詳細ビデオプロトコルは、フィールドに新しい実践者が、高真空、無酸素環境における薄膜の物理蒸着法に関連する様々な一般的な問題を回避するためのものです。

<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

ここで無種子およびテンプレート・フリー技術は室温で高真空中で熱蒸着を通じて、ビスマスナノワイヤを成長スケーラブルすることが実証されています。従来の金属薄膜、熱蒸着堆積物の製造のためにビスマスたてマグネトロンスパッタリングまたは熱蒸着によって堆積させ、RTで開催されたバナジウムの平らな薄膜、オーバー垂直単結晶ナノワイヤの配列に予約。成長基板の温度を制御することにより、ナノワイヤの長さと幅が広い範囲にわたって調整することができます。この新規な技術のための責任は、バナジウム薄膜の穏やかな空孔率にルーツ以前に知られていないナノワイヤ成長メカニズムです。バナジウム細孔に浸潤、ビスマスドメイン（〜1 nm）は、それらの融点を抑制し、連続してナノワイヤを形成するために、バナジウム行列からそれらを排出過度の表面エネルギーを有します。この発見は、スケーラブルな気相シンセの実現可能性を実証します任意の触媒を使用することなく、高純度のナノ材料のESIS。

バナジウム下地層の断面SEM像マグネトロンスパッタリングによって形成され、熱蒸着方法は、図2に示されている。走査型電子顕微鏡（SEM）画像は、異なる基板温度（ 図3）に形成されたビスマスのナノワイヤのために提示されています。ビスマスのナノワイヤの結晶構造は、透過型電子顕微鏡（TEM）、選択領域の電子回折（SAED）、及びX線回折（XRD）研究（ 図4...

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.

真空熱蒸発によりビスマスナノワイヤーアレイの成長シードレス

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

Research

JoVE Journal

Engineering

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

ビデオ: 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.

製造、ち密化、および3Dカーボンナノチューブの微細構造のレプリカ成形

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

工学

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.

カーボンナノチューブアレイの濡れ特性をチューニングするための処置をアニーリングドライ酸化と真空

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.

任意の基板上の垂直配向小分子有機ナノワイヤーの超高密度アレイ

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.

シングルGaNナノ細線デバイスのための接触界面の解析

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.

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.

複合酸化物薄膜のエピタキシャル成長のために原子的に定義されたテンプレート

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

化学

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.

高イオン強度ソリューションで感知するためのカーボンナノチューブ高周波ナノエレクトロニクスバイオセンサーの作製

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

生物工学

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.

アクティブな表面の成長メカニズムを介して基質結合 Au ナノワイヤの作製

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.

二次元ナノエレクトロニクスを作製する標準および信頼性の高いメソッド

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.

プラズマ援用分子線エピタキシー法により成長した Zn 極性 ZnO/BeMgZnO へテロ構造をショットキー ダイオードの作製

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

真空熱蒸発によりビスマスナノワイヤーアレイの成長シードレス

要約

さらに動画を探す

この動画の章

製造、ち密化、および3Dカーボンナノチューブの微細構造のレプリカ成形

カーボンナノチューブアレイの濡れ特性をチューニングするための処置をアニーリングドライ酸化と真空

任意の基板上の垂直配向小分子有機ナノワイヤーの超高密度アレイ

シングルGaNナノ細線デバイスのための接触界面の解析

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

複合酸化物薄膜のエピタキシャル成長のために原子的に定義されたテンプレート

高イオン強度ソリューションで感知するためのカーボンナノチューブ高周波ナノエレクトロニクスバイオセンサーの作製

アクティブな表面の成長メカニズムを介して基質結合 Au ナノワイヤの作製

二次元ナノエレクトロニクスを作製する標準および信頼性の高いメソッド

プラズマ援用分子線エピタキシー法により成長した Zn 極性 ZnO/BeMgZnO へテロ構造をショットキーダイオードの作製

真空熱蒸発によりビスマスナノワイヤーアレイの成長シードレス

要約

さらに動画を探す

この動画の章

製造、ち密化、および3Dカーボンナノチューブの微細構造のレプリカ成形

カーボンナノチューブアレイの濡れ特性をチューニングするための処置をアニーリングドライ酸化と真空

任意の基板上の垂直配向小分子有機ナノワイヤーの超高密度アレイ

シングルGaNナノ細線デバイスのための接触界面の解析

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

複合酸化物薄膜のエピタキシャル成長のために原子的に定義されたテンプレート

高イオン強度ソリューションで感知するためのカーボンナノチューブ高周波ナノエレクトロニクスバイオセンサーの作製

アクティブな表面の成長メカニズムを介して基質結合 Au ナノワイヤの作製

二次元ナノエレクトロニクスを作製する標準および信頼性の高いメソッド

プラズマ援用分子線エピタキシー法により成長した Zn 極性 ZnO/BeMgZnO へテロ構造をショットキー ダイオードの作製

プラズマ援用分子線エピタキシー法により成長した Zn 極性 ZnO/BeMgZnO へテロ構造をショットキーダイオードの作製