ダイヤモンドから同位体ホモジャンクションバンドの工学
H Watanabe1, C E Nebel, S Shikata
1Diamond Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2-13, 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568, Japan. hideyuki-watanabe@aist.go.jp
Science (New York, N.Y.)
|June 13, 2009
まとめ
研究者は,電子を閉じ込めるために,炭素12と炭素13の同位体を用いてダイヤモンドの超格子を作り出した. この新しいアプローチは,ダイヤモンドの有能なキャリア閉じ込めを実証し,新しい半導体アプリケーションの道を開く.
科学分野:
- マテリアルサイエンス 材料科学
- 凝縮物質物理学 凝縮物質物理学
- 量子工学は,量子工学である.
背景:
- 半導体電荷キャリアの閉じ込めは,通常,異なる元素組成のヘテロ構造を用いて達成されます.
- 例として,アルミニウムガリウムアルゼン化物 (AlGaAs) とガリウムアルゼン化物 (GaAs) の層が挙げられます.
研究 の 目的:
- 同位体的に純粋な炭素同位体を用いてダイヤモンドのスーパーラットスを製造し,特徴づけます.
- エンジニアリングされたバンドギャップ差異によるダイヤモンドのキャリア閉じ込めを実証するために.
主な方法:
- 炭素12 (12C) と炭素13 (13C) の同位素を用いた多層ダイヤモンド構造の製造.
- バンドギャップのエネルギー差が17ミリエレクトロンボルトで閉じ込められている.
- エキソニック再結合を分析するために80ケルビンでのカトドロルミネスセンスのスペクトロスコーピー.
主要な成果:
- 薄い (30 nm) 層と厚い (350 nmまで) 層の両方を持つダイヤモンドのスーパーラットスの製造に成功しました.
- 高エネルギー13C帯から低エネルギー12C帯にシフトするエキソニン再結合の観測.
- ダイヤモンドの超格子構造内の効果的な電子閉じ込めの実証.
結論:
- 異なる炭素同位体から成るダイヤモンドの超網状は,電荷キャリアを効果的に閉じ込めることができます.
- この同位体工学のアプローチは,ダイヤモンドに量子井戸を作り出すための新しい方法を提供します.
- この発見は,先端のダイヤモンドベースの電子機器や光電子機器の開発の可能性を広げている.
関連する概念動画
01:01Energy Bands in Solids
Isolated atoms have discrete energy levels that are well described by the Bohr model. And, it quantifies the energy of an electron in a hydrogen atom as En. Higher quantum numbers 'n' yield less negative, closer electron energy levels.
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states that no two...
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states that no two...
01:04¹³C NMR: ¹H–¹³C Decoupling
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
03:35Hybridization of Atomic Orbitals II
sp3d and sp3d 2 Hybridization
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
02:35Band Theory
When two or more atoms come together to form a molecule, their atomic orbitals combine and molecular orbitals of distinct energies result. In a solid, there are a large number of atoms, and therefore a large number of atomic orbitals that may be combined into molecular orbitals. These groups of molecular orbitals are so closely placed together to form continuous regions of energies, known as the bands.
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...