分子結合におけるHOMOの配列と接触抵抗の相関関係:芳香的チオールと芳香的イソシアン化物
BongSoo Kim1, Jeremy M Beebe, Yongseok Jun
1Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Journal of the American Chemical Society
|April 13, 2006
まとめ
金-分子-金属の結合を調査すると,金-イソシアン化物接触は,より高いエネルギーバリアにより,金-チオール接触よりも抵抗性が高いことが明らかになる. この差は伝導性に影響するが,分子結合の長さの依存には影響しない.
科学分野:
- 分子電子は分子電子である.
- 表面科学とは,地表科学のことである.
- 凝縮物質物理学 凝縮物質物理学
背景:
- 金属-分子-金属 (MMM) 結合における電子輸送は,分子電子学にとって極めて重要です.
- 導電性は,金属分子接触と分子電子構造に依存する.
研究 の 目的:
- 結合オリゴアセンの電子伝送特性およびバレンスの電子構造を調査する.
- チオール (-S) とイソシアン化物 (-CN) のリンク器が金基結合における伝導性に及ぼす効果を比較する.
主な方法:
- 導管探査機原子力顕微鏡 (CP-AFM) を用いて,結合抵抗を測定する.
- 紫外線光電子スペクトロスコーピー (UPS) は,バレンスの電子構造と分子軌道エネルギーを決定します.
主要な成果:
- 金-イソシアン化物 (Au-CN) 接触器は,金-チオール (Au-S) 接触器よりも高い耐性を示す.
- UPSのデータは,最も高い分子オービタル (HOMO) が,イソシアン化物結合分子のエネルギーが低いことを示しており,コンタクトでより大きなトンネルバリアを示しています.
- HOMO値の違いは,交差点抵抗の長さ依存 (ベータ値) に有意な影響を与えない.
結論:
- メタル-リンクアー・インターフェースの性質は,分子結合における接触抵抗の決定的な決定因子である.
- HOMOの位置によって探知される金属分子界面のエネルギーレベルの調整は,トンネルバリアに影響します.
- これらの結合系では,抵抗の変動を決定する際には,接触特性が分子骨幹の長さよりも優位である.
関連する概念動画
00:26Hydrogen Bonds
Hydrogen BondsHydrogen bonds are weak attractions between atoms that have formed other chemical bonds. One of these atoms is electronegative, like oxygen, and has a partial negative charge. The other is a hydrogen atom that has bonded with another electronegative atom and has a partial positive charge.Hydrogen Bonds Control the World!Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are...
03:37Molecular Shape and Polarity
Dipole Moment of a Molecule
03:13Intermolecular Forces
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen bonds, and dispersion...
02:34Comparing Intermolecular Forces: Melting Point, Boiling Point, and Miscibility
Intermolecular forces are attractive forces that exist between molecules. They dictate several bulk properties, such as melting points, boiling points, and solubilities (miscibilities) of substances. Molar mass, molecular shape, and polarity affect the strength of different intermolecular forces, which influence the magnitude of physical properties across a family of molecules.
Temporary attractive forces like dispersion are present in all molecules, whether they are polar or nonpolar. They...
Temporary attractive forces like dispersion are present in all molecules, whether they are polar or nonpolar. They...
01:04Structures of Aldehydes and Ketones
Vanillin—a flavoring agent in vanilla, cinnamaldehyde—a molecule responsible for the distinct smell of cinnamon, and acetone—a strong-smelling ingredient in nail polish removers, all belong to a class of carbonyl compounds called aldehydes and ketones (Figure 1). Although both aldehydes and ketones contain the characteristic carbonyl (C=O) bond, their chemical structures vary with respect to the groups directly attached to the carbonyl carbon.
In aldehydes (Figures 1a and 1b), the carbonyl...
In aldehydes (Figures 1a and 1b), the carbonyl...
01:04Hydrogen Bonds
A hydrogen bond is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for example, the oxygen in the water molecule) is attracted to another electronegative atom from another polar molecule, such as water (H2O), hydrogen fluoride (HF), or ammonia (NH3). The huge electronegativity difference between the H atom (2.1) and the atom to which it is bonded (4.0 for an F atom, 3.5 for an O atom, or 3.0 for an N atom), combined with the very small size of an H atom...