Presentation Information
[17p-B4-6]Negative Differential Resistance in Single-Molecule Junctions Based on Heteroepitaxial Spherical Au/Pt Nanogap Electrodes
〇(D)Dongbao Yin1, Miku Furushima2, Haru Tanaka1, Seiichiro Izawa1, Tomoya Ono2, Ryo Shintani3, Yutaka Majima1 (1.Tokyo Tech, 2.Kobe Univ., 3.Osaka Univ.)
Keywords:
electroless gold plating,single-molecule junctions,negative differential resistance
Single-molecule junctions have established a variety of functional quantum devices working based on the molecular orbitals of individual molecules. The single-molecule junctions exhibiting negative differential resistance (NDR) behaviors, characterized by a decrease in current with increasing voltage, have attracted considerable attention due to their potential application as ultra-fast resonant tunneling diodes. Thus, several pioneering studies have investigated the mechanisms behind this nonlinear NDR behavior through theoretical modeling and experimental evaluation. However, the peak-to-valley (PV) ratios of NDR observed in most single-molecule junctions are relatively small (< 10). The large-scale fabrication and integration of electronic devices also highlight a demand to create a platform for constructing solid-state single-molecule junctions.
Recently, we have developed heteroepitaxial spherical (HS)-Au/Pt nanogap electrodes prepared by electron-beam lithography (EBL) and self-termination electroless gold plating (ELGP). Their molecular length gap separation, small radii, and robust thermal stability enable large-scale multiple fabrication of single-molecule junctions on a Si substrate using interested molecules.
Here, we report a pronounced NDR effect with a PV ratio of 30.1 on a single-molecule junction consisting of a π-conjugated quinoidal-fused oligosilole derivative, Si2×2, embedded between HS-Au/Pt nanogap electrodes. This NDR effect persists over a consecutive 180 current traces and showed stable temperature dependence between 9 K and 300 K. Density functional theory calculations under electric fields suggest that the NDR effect arises from bias-dependent resonant tunneling transport via the polarized highest occupied molecular orbital (HOMO). Our findings demonstrate a promising electrical platform for constructing functional quantum devices at the single-molecule level.
Recently, we have developed heteroepitaxial spherical (HS)-Au/Pt nanogap electrodes prepared by electron-beam lithography (EBL) and self-termination electroless gold plating (ELGP). Their molecular length gap separation, small radii, and robust thermal stability enable large-scale multiple fabrication of single-molecule junctions on a Si substrate using interested molecules.
Here, we report a pronounced NDR effect with a PV ratio of 30.1 on a single-molecule junction consisting of a π-conjugated quinoidal-fused oligosilole derivative, Si2×2, embedded between HS-Au/Pt nanogap electrodes. This NDR effect persists over a consecutive 180 current traces and showed stable temperature dependence between 9 K and 300 K. Density functional theory calculations under electric fields suggest that the NDR effect arises from bias-dependent resonant tunneling transport via the polarized highest occupied molecular orbital (HOMO). Our findings demonstrate a promising electrical platform for constructing functional quantum devices at the single-molecule level.
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