Name: silicon metal-oxide-semiconductor quantum dots for single-electron pumping
Uploaded: 2015-06-03T15:00:00.000+00:00
Duration: 14 min 58 s
Description: Watch this Scientific Journal Video about Silicon Metal-oxide-semiconductor Quantum Dots for Single-electron Pumping at JoVE.com

私たちは、有益な議論のためのKYタン、P.参照およびGC Tettamanziに感謝します。我々は、オーストラリアの研究評議会（認可番号DP120104710）、フィンランドアカデミー（認可番号251748、135794、272806）およびデバイス製造のためのオーストラリア国立加工施設からのサポートからの財政支援を認めます。 ARは、ニューサウスウェールズ大学の初期のキャリア研究の助成スキームからの財政支援を認めるものです。 MicroNova社ナノファブリケーションセンターのアールト大学の設備と技術サポートの提供も認められています。

注：このプロトコルは、製造、パッケージとシリコンMOS QD技術に基づいた単一電子ポンプをテストするために使用する手順について説明します。項3のものはISO6研究所で行われている間、サブセクション1及び2で説明したステップは、ISO5クリーンルームで行われます。周囲条件を連続的に制御されます。温度と湿度の公称値は、それぞれ、20±1℃、55％±5％に設定されています。 1.微細加工<ol><li>フィールド酸化物<ol><li>以下に浸漬することによって、ウエハを清掃してください：ピラニアエッチング（10分）、脱イオン（DI）水（10分）、RCA-2溶液（DI水175ミリリットル、塩酸30ミリリットル、H 2 O 2 30ミリリットル、100℃で10分間）を水に10希釈し、脱イオン水（5分）、フッ化水素（HF）酸：1（10秒）、DI水（10分）。 HF（ すなわち 、ゴーグル、PVCエプロン、とPVC手袋）を取り扱う際は防護服を使用してください。順に進みます。 </li><li>ウエハを配置900℃での酸化炉で、次のように段階的に酸化する：ドライO 2（10分）、湿潤O 2（40分）、ドライO 2（10分）、N 2（15分）。 </li></ol></li><li>オーミックコンタクト<ol><li>フォトリソグラフィとエッチングの酸化を行います。 <ol><li>次のようにウエハ表面上に接着促進ヘキサメチルジシラザン（HMDS）の数nmの厚さの層を堆積させる：プリベークをホットプレート上で110℃で1分間、ガラスビーカーにHMDSの約50ミリリットル注ぎ、ビーカーを置きます真空チャンバ内のウエハは、避難、2分間待ちます。 </li><li>バックとウェハ（3,000〜5,000 rpmで、所望の厚さに応じて25〜40秒）の前面両側のフォトレジストの2-4μmの厚さの層をスピン。 </li><li>マスクアライナーで紫外光に露出させ（4-10秒を10mW / cm 2の厚さに抵抗するようによります）。 1分間110℃のホットプレート上でポストベーク。 </li><li>次いで脱イオン水ですすぎ、1〜2分間の開発。 </LI&gt; <li> 20分間O 2プラズマエッチングを行う（;入射パワー= 50 W;圧力= 340ミリトール反射電力を&lt;1 W）。 </li><li>緩衝HF酸エッチング溶液中で酸化物（15：1、4-5分、30℃で≈速度は20nm /分のエッチング）。脱イオン水（5分）ですすいでください。 N 2でブロー乾燥。 </li></ol></li><li>アセトンに浸漬することにより、フォトレジストを除去します。イソプロパノール（IPA）で、その後、N 2でブロー乾燥すすいでください。 </li><li> （所望のドーピング濃度に応じて30〜45分間、N 2流量）リン源と1000℃の炉内でウェハを配置します。 </li><li>脱イオン水（10分）ですすぎ、水で希釈したHF酸（1、3-4分間、30℃でのエッチング速度≈は40nm / minで10）で汚染された酸化物層を除去します。 </li><li> 1.1.2のように酸化します。 </li></ol></li><li>ゲート酸化物<ol><li>繰り返しは1.2.1と1.2.2を繰り返します。 </li><li> 800℃で、専用の炉内でウェハを置き、次のように段階的に酸化する：ドライO 2（10分）、Dichloroethylene + O 2（20分）、ドライO 2（所望の酸化物の厚さに応じて10〜30分）、N 2（15分）。 </li></ol></li><li>オーミックコンタクトのメタライゼーション<ol><li>手順を繰り返し1.2.1。 </li><li>電子ビーム蒸発器内のウエハを配置します。 0.2〜0.5ナノメートル/秒、5×10 -6トルで100nmのアルミニウムを蒸発させます。 </li><li>金属をリフトオフするために1時間80℃でホットプレート上でNメチル-2-ピロリドン（NMP）中にウェハを浸します。必要に応じて超音波攪拌を使用してください。 2分間IPAですすいでください。 N 2でブロー乾燥。 </li><li>少なくとも15分間、400℃で形成ガスでアニール。 </li></ol></li></ol> 2.ナノ加工<ol><li>ウェーハダイシング<ol><li>いずれかが（ポリマーおよび紡糸パラメータの種類は、この段階では無関係である）保護コーティングとして機能するように、ウェハ上にレジストをスピン。 </li><li> 〜10×2 mm 2での個々のチップにウェハを切断するためにダイヤモンドチップダイサーを使用してください。 </li></ol></li><li>クリーニング<ol><li>その後2分間IPAですすぎ、80℃のホットプレート上で1時間、NMP中に浸します。 N 2でブロー乾燥。 </li><li> 5分間O 2プラズマエッチングを行う（= 50 W入射電力、反射電力を&lt;1 W）。 </li><li>アセトン、IPAでクリーンスピン（7,500 rpmで、30秒） </li></ol></li><li>アライメントマーカパターニング<ol><li>スピンポリメチルメタクリレート（PMMA 950k）はA4は（30秒が所望の厚さに応じて、5,000-7,500 rpm）をレジスト。典型的な加工厚≈150〜200ナノメートル。 90秒間180℃のホットプレート上にレジストを焼きます。 </li><li>電子ビームリソグラフィを実施しています。次の書き込み条件を使用し= 30keVのビームエネルギー、ビーム電流≈30 PA、面積線量500〜650μC/ cm 2でのマーカーの大きさに応じて≈およびレジスト厚。 </li><li> （1：3）40〜60秒間、その後20秒間IPAですすぎ、メチルイソブチルケトン、IPA溶液のレジストの開発。 N 2銃でブロー乾燥。 </li><li>場所電子ビーム蒸発器内のチップ。 0.2〜0.4ナノメートル/秒、5×10 -6トルでのTiの15 nmおよびPtを65ナノメートルを蒸発させます。 </li><li>ステップ1.4.3のように金属を持ち上げ。 </li><li>ステップのようにきれいなチップ2.2.2-2.2.3。 </li></ol></li><li>ゲートパターニング<ol><li>スピンは、2.3.1のように抵抗します。 </li><li>電子ビームリソグラフィを実施しています。 = 30 keVのビームエネルギー、ビーム電流≈30 PA、面積線量≈は500〜700μC/ cm 2の高解像度の特徴については、以下の書き込み条件を使用してください。低解像度の機能のための条件を書く：= 15 keVのビームエネルギー、ビーム電流≈10 nAの、面積線量400〜600μC/ cm 2の ≈。 </li><li> 2.3.3のようにレジストを開発します。 </li><li>熱蒸発器内のチップを配置します。 0.1〜0.4ナノメートル/秒、1-9×10 -6ミリバールでのAlを蒸発させます。目標厚さは、レイヤ1のためのレイヤ数に応じて、 図2（b）に示すように（25〜35ナノメートル、レイヤ2、75〜90 45〜65 nmのために変化するn個レイヤ3のためのM）。 </li><li>ステップ1.4.3のように金属を持ち上げ。 </li><li> 5〜10分間、150℃のホットプレート上でのAlの酸化を行います。 </li><li>ステップ2.2.3のようにきれいなチップ。 </li><li>手順を繰り返し二回3層ゲートスタックを実現する2.4.1-2.4.7。 </li></ol></li></ol> 3.デバイスのパッケージング<ol><li>ステップ2.1のようにサイコロチップ</li><li> 2分間アセトン及びIPAの結果小さなチップをすすぎます。 </li><li> PMMA A5を有するプリント回路基板（PCB）の個片を接着。それが乾燥するために2分を待ちます。あるいは、熱化を強化するために、銀エポキシ樹脂を使用しています。 </li><li>ウェッジボンダにPCBをロードして、配線を進めます。 </li></ol> 4.デバイスの完全性テスト<ol><li>ディッププローブに有線デバイスを含むPCBをマウントします。 </li><li>ディッププローブのものにPCBの電線を配線します。 </li><li>液体ヘリウムを含む容器内にプローブを挿入します。過剰なヘリウムbを避けるために、ゆっくりと進みオイルオフ。 </li><li>接地他のゲートを維持しながら、各デバイスのゲートについては、ソースメジャーユニットへのプローブの対応する室温の電極を接続してください。数NAにコンプライアンス電流を設定します。 、0.1 Vのステップで1.5Vにゼロからの電圧を掃引測定し、電流を記録します。 </li><li>バッテリ駆動の可変DC電圧源に各ゲート線を接続し、内蔵のロックインアンプの交流電圧源、及びロックイン増幅器の入力ポートにドレイン線にソース線。 </li><li> （ 図4参照）は、異なるゲート電圧の設定のためのコンダクタンスを排出するソースを測定します。 <ol><li>グローバル接地C1とC2ゲートを維持することによりゲートBL、BR、PL、SLおよびDLに印加される電圧をランプアップ。 「ターン·オン」デバイス特性を記録します。 </li><li>個別に各ゲート電圧を下降し、ゲート「ピンチオフ」の特性を記録します。 </li><li>静電クを定義するためにゲート電圧を調整しますターンオン電圧より（大きい）、BLとBR（PL、SLおよびDL）の電圧を設定することによりアントゥムドット小さいです。クーロンブロッケード特性を記録します。 </li></ol></li></ol>

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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=Stabilization+of+single-electron+pumps+by+high+magnetic+fields.">Stabilization of single-electron pumps by high magnetic fields.</a> Phys. Rev. B. 86 (15), 155311-1-155311-6 (2012).</li><li>Kataoka, 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=Tunable+Nonadiabatic+Excitation+in+a+Single-Electron+Quantum+Dot.">Tunable Nonadiabatic Excitation in a Single-Electron Quantum Dot.</a> Phys. Rev. Lett. 106 (12), 126801-1-126801-4 (2011).</li></ol>

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本論文で報告されたプロトコルは、その機能の完全性をテストし、単電子ポンプとして、それらを動作させるために、シリコンMOSのQD、ならびに実験手順を製造するための技術について説明します。注目すべきことに、ゲート設計を調整することによって、同一の製造工程では、量子ビットの読み出しおよび制御17に適し、ならびに12,13チャージポンプデバイスを製造するために使用することができます。我々は、この記事で引用されたプロセスの多くのパラメータは（キャリブレーション、作るか、またはモデル）を使用し、製造ツールのと同様に、シリコン基板（厚さとバックグラウンドドーピング密度）の種類に応じて変えることができることに注意してください。そのようなリソグラフィ露光量または現像時間、エッチングや酸化時間等の数量は、慎重に較正されかつ信頼性の高い歩留まりを確保するためにテストされなければなりません。さらに、異なるプロセスのために同じ製造ツールの使用に起因するクロスコンタミネーションを避けるために重要です。この目的のために、数のCriticalステップはもっぱら、金属蒸発、酸素炉とHF浴などのシリコン処理専用の機器を用いて実施されます。 より一般的には、シリコンは、チャージポンプ18〜20を実現するための最適な材料として関心の高まりを描いています。これは、一部の業界互換のシリコンプロセスを使用して、新しい量子ベース電流の標準を実装する魅力的観点によるものです。これは、スケーラビリティ、並列駆動のオーバーヘッドのためのよく確立され、信頼性の高い統合技術の恩恵を受けるだろう。重要なことには、ゲート材料のような伝統的な金属を含まない完全な相補型MOS（CMOS）技術は、単一の電子デバイス21に大幅に減少した背景の電荷の変動を示しています。このような変動は計量精度を達成するために有害であることができます。 ここで説明するプロトコルは、金属ゲートを有するMOSナノデバイスの実現に制限されています。したがって、achieへ完全な産業適合性をまして電荷変動を低減するには、ゲート堆積技術を変更し、ゲート材料として高濃度にドープされた多結晶シリコンを使用するために必要とされるであろう。 結論として、ここで説明したMOS QDポンプは最近、正確な電流発生13の面で非常に優れた性能を有するシリコンの技術的利点を組み合わせています。これは、1つは、コンパクトで汎用性の高いシステムにつながる複数のゲート層を積層することを可能にする設計及び製造プロセスの高い柔軟性に由来します。一緒に背景の電荷の変動を減少させる可能性のあるドットの静電閉じ込めの結果として生じる微調整可能性は、他の半導体のポンプ22,23で観察された主な課題を克服するための段階を設定します。

Silicon is the material of choice for most of the modern microelectronics. Its properties, combined with advanced lithographic techniques, have allowed the semiconductor industry to achieve very large-scale integration and deliver billions of transistors per chip. The metal-oxide-semiconductor (MOS) technology1 has been the key of this relentless technological progress2. In brief, it is based on a selectively doped Si substrate which is thermally oxidized to grow a high quality SiO2 gate oxide on which a metal gate electrode is deposited. Recently, it has been shown that the use of a stack of gate oxides could be beneficial3 . While present industry standards have reached minimum feature sizes for gate lengths below 20 nm, it is becoming increasingly evident that, at this level of miniaturization, detrimental quantum mechanical phenomena come into play that may complicate further downscaling4.
Remarkably, silicon is also an excellent host material to exploit the quantum properties of the electron charge and spin5. This has broadened its range of applicability to entirely new fields such as quantum computing6 and quantum electrical metrology7. Among other approaches5, the use of a multi-gate MOS technology8,9 has led to electrostatically-defined quantum dots (QD) whose occupancy can be controlled down to single-electron level10. Unlike the conventional MOS process where just one gate per transistor is needed1, these QDs are defined via a three-layer stack of Al/AlyOx gates which are used to selectively accumulate electrons at the Si/SiO2 interface, as well as provide lateral and vertical confinement11.
Although these devices had been originally developed for quantum computing applications, they have also recently shown promising performances as metrological tools12,13. In the field of quantum electrical metrology, a long-standing goal is the redefinition of the unit ampere in terms of the elementary charge (e) 14. In particular, the emphasis is on the realization of nano-scale charge pumps to clock the transfer of individual electrons timely and accurately. These devices generate macroscopic quantized electric currents, I=nef, where f is the frequency of an external driving oscillator and n is an integer. To date, the best performance has been achieved with a GaAs-based pump by yielding a current in excess of 150 pA with a relative uncertainty of 1.2 parts per million15. Recently, silicon MOS QDs have also stood out for the implementation of highly accurate single-electron pumps thanks to the capability of finely tuning the charge confinement13.
Here, we discuss the protocol used for the fabrication of silicon MOS QDs. Furthermore, the cryogenic set-up used to test the integrity of the devices after fabrication and the one to perform charge pumping experiments are described. Finally, representative measurements of quantized electric current are reported.

<table><tbody><tr><td>Silicon wafers</td><td>TOPSIL</td><td></td><td>4 inch</td></tr><tr><td>Electron-beam lithography machine</td><td>Raith gmbh</td><td></td><td>Raith 150two</td></tr><tr><td>E-beam resist&amp;nbsp;</td><td>MicroChem gmbh</td><td></td><td>PMMA</td></tr><tr><td>Photoresist</td><td>MicroChem gmbh</td><td></td><td>nLOF2020</td></tr><tr><td>Mask aligner</td><td>Quintel</td><td></td><td>Q6000</td></tr><tr><td>Photoresist developer</td><td>MicroChem gmbh</td><td></td><td>AZ826MIF</td></tr></tbody></table>

silicon metal-oxide-semiconductor quantum dots for single-electron pumping

As mass-produced silicon transistors have reached the nano-scale, their behavior and performances are increasingly affected, and often deteriorated, by quantum mechanical effects such as tunneling through single dopants, scattering via interface defects, and discrete trap charge states. However, progress in silicon technology has shown that these phenomena can be harnessed and exploited for a new class of quantum-based electronics. Among others, multi-layer-gated silicon metal-oxide-semiconductor (MOS) technology can be used to control single charge or spin confined in electrostatically-defined quantum dots (QD). These QD-based devices are an excellent platform for quantum computing applications and, recently, it has been demonstrated that they can also be used as single-electron pumps, which are accurate sources of quantized current for metrological purposes. Here, we discuss in detail the fabrication protocol for silicon MOS QDs which is relevant to both quantum computing and quantum metrology applications. Moreover, we describe characterization methods to test the integrity of the devices after fabrication. Finally, we give a brief description of the measurement set-up used for charge pumping experiments and show representative results of electric current quantization.

Watch this Scientific Journal Video about Silicon Metal-oxide-semiconductor Quantum Dots for Single-electron Pumping at JoVE.com

Silicon Metal-oxide-semiconductor Quantum Dots for Single-electron Pumping

The fabrication process and experimental characterization techniques relevant to single-electron pumps based on silicon metal-oxide-semiconductor quantum dots are discussed.

単電子揚水用のシリコン金属酸化膜半導体量子ドット

As mass-produced silicon transistors have reached the nano-scale, their behavior and performances are increasingly affected, and often deteriorated, by ...

silicon-metal-oxide-semiconductor-quantum-dots-for-single-electron

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14.4K ビュー.  University of New South Wales. The fabrication process and experimental characterization techniques relevant to single-electron pumps based on silicon metal-oxide-semiconductor quantum dots are discussed.

ビデオ: Silicon Metal-oxide-semiconductor Quantum Dots for Single-electron Pumping

Compact Quantum Dots for Single-molecule Imaging

Single-molecule imaging is an important tool for understanding the mechanisms of biomolecular function and for visualizing the spatial and temporal heterogeneity of molecular behaviors that underlie cellular biology 1-4. To image an individual molecule of interest, it is typically conjugated to a fluorescent tag (dye, protein, bead, or quantum dot) and observed with epifluorescence or total internal reflection fluorescence (TIRF) microscopy. While dyes and fluorescent proteins have been the mainstay of fluorescence imaging for decades, their fluorescence is unstable under high photon fluxes necessary to observe individual molecules, yielding only a few seconds of observation before complete loss of signal. Latex beads and dye-labeled beads provide improved signal stability but at the expense of drastically larger hydrodynamic size, which can deleteriously alter the diffusion and behavior of the molecule under study.
Quantum dots (QDs) offer a balance between these two problematic regimes. These nanoparticles are composed of semiconductor materials and can be engineered with a hydrodynamically compact size with exceptional resistance to photodegradation 5. Thus in recent years QDs have been instrumental in enabling long-term observation of complex macromolecular behavior on the single molecule level. However these particles have still been found to exhibit impaired diffusion in crowded molecular environments such as the cellular cytoplasm and the neuronal synaptic cleft, where their sizes are still too large 4,6,7.
Recently we have engineered the cores and surface coatings of QDs for minimized hydrodynamic size, while balancing offsets to colloidal stability, photostability, brightness, and nonspecific binding that have hindered the utility of compact QDs in the past 8,9. The goal of this article is to demonstrate the synthesis, modification, and characterization of these optimized nanocrystals, composed of an alloyed HgxCd1-xSe core coated with an insulating CdyZn1-yS shell, further coated with a multidentate polymer ligand modified with short polyethylene glycol (PEG) chains (Figure 1). Compared with conventional CdSe nanocrystals, HgxCd1-xSe alloys offer greater quantum yields of fluorescence, fluorescence at red and near-infrared wavelengths for enhanced signal-to-noise in cells, and excitation at non-cytotoxic visible wavelengths. Multidentate polymer coatings bind to the nanocrystal surface in a closed and flat conformation to minimize hydrodynamic size, and PEG neutralizes the surface charge to minimize nonspecific binding to cells and biomolecules. The end result is a brightly fluorescent nanocrystal with emission between 550-800 nm and a total hydrodynamic size near 12 nm. This is in the same size range as many soluble globular proteins in cells, and substantially smaller than conventional PEGylated QDs (25-35 nm).

We describe the preparation of colloidal quantum dots with minimized hydrodynamic size for single-molecule fluorescence imaging. Compared to conventional quantum dots, these nanoparticles are similar in size to globular proteins and are optimized for single-molecule brightness, stability against photodegradation, and resistance to nonspecific binding to proteins and cells.

1分子蛍光イメージングのためのコンパクトな量子ドット

Single-molecule imaging is an important tool for  understanding the mechanisms of biomolecular function and for visualizing the  spatial and temporal ...

工学

Gradient Echo Quantum Memory in Warm Atomic Vapor

Gradient echo memory (GEM) is a protocol for storing optical quantum states of light in atomic ensembles. The primary motivation for such a technology is that quantum key distribution (QKD), which uses Heisenberg uncertainty to guarantee security of cryptographic keys, is limited in transmission distance. The development of a quantum repeater is a possible path to extend QKD range, but a repeater will need a quantum memory. In our experiments we use a gas of rubidium 87 vapor that is contained in a warm gas cell. This makes the scheme particularly simple. It is also a highly versatile scheme that enables in-memory refinement of the stored state, such as frequency shifting and bandwidth manipulation. The basis of the GEM protocol is to absorb the light into an ensemble of atoms that has been prepared in a magnetic field gradient. The reversal of this gradient leads to rephasing of the atomic polarization and thus recall of the stored optical state. We will outline how we prepare the atoms and this gradient and also describe some of the pitfalls that need to be avoided, in particular four-wave mixing, which can give rise to optical gain.

The gradient echo memory is a protocol for storing optical quantum states of light in atomic ensembles. Quantum memory is a key element of a quantum repeater, which can extend the range of quantum key distribution. We outline the operation of the scheme when implemented in a 3-level atomic ensemble.

暖かい原子蒸気に勾配エコー量子メモリ

Gradient  echo memory (GEM) is a protocol for storing optical quantum states of light in  atomic ensembles. The primary motivation for such a technology ...

Nanofabrication of Gate-defined GaAs/AlGaAs Lateral Quantum Dots

A quantum computer is a computer composed of quantum bits (qubits) that takes advantage of quantum effects, such as superposition of states and entanglement, to solve certain problems exponentially faster than with the best known algorithms on a classical computer. Gate-defined lateral quantum dots on GaAs/AlGaAs are one of many avenues explored for the implementation of a qubit. When properly fabricated, such a device is able to trap a small number of electrons in a certain region of space. The spin states of these electrons can then be used to implement the logical 0 and 1 of the quantum bit. Given the nanometer scale of these quantum dots, cleanroom facilities offering specialized equipment- such as scanning electron microscopes and e-beam evaporators- are required for their fabrication. Great care must be taken throughout the fabrication process to maintain cleanliness of the sample surface and to avoid damaging the fragile gates of the structure. This paper presents the detailed fabrication protocol of gate-defined lateral quantum dots from the wafer to a working device. Characterization methods and representative results are also briefly discussed. Although this paper concentrates on double quantum dots, the fabrication process remains the same for single or triple dots or even arrays of quantum dots. Moreover, the protocol can be adapted to fabricate lateral quantum dots on other substrates, such as Si/SiGe.

This paper presents a detailed fabrication protocol for gate-defined semiconductor lateral quantum dots on gallium arsenide heterostructures. These nanoscale devices are used to trap few electrons for use as quantum bits in quantum information processing or for other mesoscopic experiments such as coherent conductance measurements.

ゲート定義のGaAs / AlGaAs系横量子ドットのナノファブリケーション

A quantum computer is a computer composed of quantum bits (qubits) that takes advantage of quantum effects, such as superposition of states and ...

Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection

The ability to perform simultaneous resonant excitation and fluorescence detection is important for quantum optical measurements of quantum dots (QDs). Resonant excitation without fluorescence detection &#8211; for example, a differential transmission measurement &#8211; can determine some properties of the emitting system, but does not allow applications or measurements based on the emitted photons. For example, the measurement of photon correlations, observation of the Mollow triplet, and realization of single photon sources all require collection of the fluorescence. Incoherent excitation with fluorescence detection &#8211; for example, above band-gap excitation &#8211; can be used to create single photon sources, but the disturbance of the environment due to the excitation reduces the indistinguishability of the photons. Single photon sources based on QDs will have to be resonantly excited to have high photon indistinguishability, and simultaneous collection of the photons will be necessary to make use of them. We demonstrate a method to resonantly excite a single QD embedded in a planar cavity by coupling the excitation beam into this cavity from the cleaved face of the sample while collecting the fluorescence along the sample&#39;s surface normal direction. By carefully matching the excitation beam to the waveguide mode of the cavity, the excitation light can couple into the cavity and interact with the QD. The scattered photons can couple to the Fabry-Perot mode of the cavity and escape in the surface normal direction. This method allows complete freedom in the detection polarization, but the excitation polarization is restricted by the propagation direction of the excitation beam. The fluorescence from the wetting layer provides a guide to align the collection path with respect to the excitation beam. The orthogonality of the excitation and detection modes enables resonant excitation of a single QD with negligible laser scattering background.

Resonant excitation of a single self-assembled quantum dot can be achieved using an excitation mode orthogonal to the fluorescence collection mode. We demonstrate a method using the waveguide and Fabry-Perot modes of a planar microcavity surrounding the quantum dots. The method allows complete freedom in the detection polarization.

直交の励起と検出を用いた平面キャビティ内 InGaAs 量子ドットの共鳴蛍光

The ability to perform simultaneous resonant excitation and fluorescence detection is important for quantum optical measurements of quantum dots (QDs). ...

All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics

The miniaturization of semiconductor devices to scales where small numbers of dopants can control device properties requires the development of new techniques capable of characterizing their dynamics. Investigating single dopants requires sub-nanometer spatial resolution, which motivates the use of scanning tunneling microscopy (STM). However, conventional STM is limited to millisecond temporal resolution. Several methods have been developed to overcome this shortcoming, including all-electronic time-resolved STM, which is used in this study to examine dopant dynamics in silicon with nanosecond resolution. The methods presented here are widely accessible and allow for local measurement of a wide variety of dynamics at the atomic scale. A novel time-resolved scanning tunneling spectroscopy technique is presented and used to efficiently search for dynamics.

We demonstrate an all-electronic method to observe nanosecond-resolved charge dynamics of dopant atoms in silicon with a scanning tunneling microscope.

すべて電子ナノ秒分解走査型トンネル顕微鏡: 単一ドーパントの電荷ダイナミクスの調査を促進します。

The miniaturization of semiconductor devices to scales where small numbers of dopants can control device properties requires the development of new ...

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape method or individual WS2 nanotubes by dispersing the suspension of WS2 nanotubes. The selected samples have been fabricated into devices by the use of the electron beam lithography and electrolyte is put on the devices. We have characterized the electronic properties of the devices under applying the gate voltage. In the small gate voltage region, ions in the electrolyte are accumulated on the surface of the samples which leads to the large electric potential drop and resultant electrostatic carrier doping at the interface. Ambipolar transfer curve has been observed in this electrostatic doping region. When the gate voltage is further increased, we met another drastic increase of source-drain current which implies that ions are intercalated into layers of WS2 and electrochemical carrier doping is realized. In such electrochemical doping region, superconductivity has been observed. The focused technique provides a powerful strategy for achieving the electric-filed-induced quantum phase transition.

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

Here, we present a protocol to control the carrier number in solids by using the electrolyte.

電解質ゲートによって WS2ナノデバイスにおける電子状態の電界制御

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape ...

Enhanced Electron Injection and Exciton Confinement for Pure Blue Quantum-Dot Light-Emitting Diodes by Introducing Partially Oxidized Aluminum Cathode

Stable and efficient red (R), green (G), and blue (B) light sources based on solution-processed quantum dots (QDs) play important roles in next-generation displays and solid-state lighting technologies. The brightness and efficiency of blue QDs-based light-emitting diodes (LEDs) remain inferior to their red and green counterparts, due to the inherently unfavorable energy levels of different colors of light. To solve these problems, a device structure should be designed to balance the injection holes and electrons into the emissive QD layer. Herein, through a simple autoxidation strategy, pure blue QD-LEDs which are highly bright and efficient are demonstrated, with a structure of ITO/PEDOT:PSS/Poly-TPD/QDs/Al:Al2O3. The autoxidized Al:Al2O3 cathode can effectively balance the injected charges and enhance radiative recombination without introducing an additional electron transport layer (ETL). As a result, high color-saturated blue QD-LEDs are achieved with a maximum luminance over 13,000 cd m-2, and a maximum current efficiency of 1.15 cd A-1. The easily controlled autoxidation procedure paves the way for achieving high-performance blue QD-LEDs.

A protocol is presented for fabricating high-performance, pure blue ZnCdS/ZnS-based quantum dots light-emitting diodes by employing an autoxidized aluminum cathode.

酸化アルミニウムの陰極の電子注入と部分的に導入することで純粋な青色量子ドット発光ダイオードの励起子閉じ込め

Stable and efficient red (R), green (G), and blue (B) light sources based on solution-processed quantum dots (QDs) play important roles in next-generation ...

Production and Targeting of Monovalent Quantum Dots

The multivalent nature of commercial quantum dots (QDs) and the difficulties associated with producing monovalent dots have limited their applications in biology, where clustering and the spatial organization of biomolecules is often the object of study. We describe here a protocol to produce monovalent quantum dots (mQDs) that can be accomplished in most biological research laboratories via a simple mixing of CdSe/ZnS core/shell QDs with phosphorothioate DNA (ptDNA) of defined length. After a single ptDNA strand has wrapped the QD, additional strands are excluded from the surface. Production of mQDs in this manner can be accomplished at small and large scale, with commercial reagents, and in minimal steps. These mQDs can be specifically directed to biological targets by hybridization to a complementary single stranded targeting DNA. We demonstrate the use of these mQDs as imaging probes by labeling SNAP-tagged Notch receptors on live mammalian cells, targeted by mQDs bearing a benzylguanine moiety.

We provide detailed instructions for the preparation of monovalent targeted quantum dots (mQDs) from phosphorothioate DNA of defined length. DNA wrapping occurs in high yield, and therefore, products do not require purification. We demonstrate the use of the SNAP tag to target mQDs to cell-surface receptors for live-cell imaging applications.

生産と一価量子ドットの標的

The multivalent nature of commercial quantum dots (QDs) and the difficulties associated with producing monovalent dots have limited their applications in ...

生物工学

Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform

To form a coherent quantum transport in hybrid superconductor-semiconductor (S-Sm) junctions, the formation of a homogeneous and barrier-free interface between two different materials is necessary. The S-Sm junction with high interface transparency will then facilitate the observation of the induced hard superconducting gap, which is the key requirement to access the topological phases (TPs) and observation of exotic quasiparticles such as Majorana zero modes (MZM) in hybrid systems. A material platform that can support observation of TPs and allows the realization of complex and branched geometries is therefore highly demanding in quantum processing and computing science and technology. Here, we introduce a two-dimensional material system and study the proximity induced superconductivity in semiconducting two-dimensional electron gas (2DEG) that is the basis of a hybrid quantum integrated circuit (QIC). The 2DEG is a 30 nm thick In0.75Ga0.25As quantum well that is buried between two In0.75Al0.25As barriers in a heterostructure. Niobium (Nb) films are used as the superconducting electrodes to form Nb- In0.75Ga0.25As -Nb Josephson junctions (JJs) that are symmetric, planar and ballistic. Two different approaches were used to form the JJs and QICs. The long junctions were fabricated photolithographically, but e-beam lithography was used for short junctions&#8217; fabrication. The coherent quantum transport measurements as a function of temperature in the presence/absence of magnetic field B are discussed. In both device fabrication approaches, the proximity induced superconducting properties were observed in the In0.75Ga0.25As 2DEG. It was found that e-beam lithographically patterned JJs of shorter lengths result in observation of induced superconducting gap at much higher temperature ranges. The results that are reproducible and clean suggesting that the hybrid 2D JJs and QICs based on In0.75Ga0.25As quantum wells could be a promising material platform to realize the real complex and scalable electronic and photonic quantum circuitry and devices.

Quantum integrated circuits (QICs) consisting of array of planar and ballistic Josephson junctions (JJs) based on In0.75Ga0.25As two-dimensional electron gas (2DEG) is demonstrated. Two different methods for fabrication of the two-dimensional (2D) JJs and QICs are discussed followed by the demonstration of quantum transport measurements in sub-Kelvin temperatures.

超伝導2次元電子ガスプラットフォーム上のスケーラブル量子集積回路

To form a coherent quantum transport in hybrid superconductor-semiconductor (S-Sm) junctions, the formation of a homogeneous and barrier-free interface ...

Synthesis of In37P20(O2CR)51 Clusters and Their Conversion to InP Quantum Dots

This text presents a method for the synthesis of In37P20(O2C14H27)51 clusters and their conversion to indium phosphide quantum dots. The In37P20(O2CR)51 clusters have been observed as intermediates in the synthesis of InP quantum dots from molecular precursors (In(O2CR)3, HO2CR, and P(SiMe3)3) and may be isolated as a pure reagent for subsequent study and use as a single-source precursor. These clusters readily convert to crystalline and relatively monodisperse samples of quasi-spherical InP quantum dots when subjected to thermolysis conditions in the absence of additional precursors above 200 &#176;C. The optical properties, morphology, and structure of both the clusters and quantum dots are confirmed using UV-Vis spectroscopy, photoluminescence spectroscopy, transmission electron microscopy, and powder X-ray diffraction. The molecular symmetry of the clusters is additionally confirmed by solution-phase 31P NMR spectroscopy. This protocol demonstrates the preparation and isolation of atomically-precise InP clusters, and their reliable and scalable conversion to InP QDs.

Synthesis of In37P20O2CR51 Clusters and Their Conversion to InP Quantum Dots

A protocol for the synthesis of In37P20(O2C14H27)51 clusters and their conversion to indium phosphide quantum dots is presented.

37P20(o2 CR)51クラスターの合成と InP 量子ドットへの変換

This text presents a method for the synthesis of In37P20(O2C14H27)51 clusters and their conversion to indium phosphide quantum dots. The In37P20(O2CR)51 ...

単電子揚水用のシリコン金属酸化膜半導体量子ドット

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