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Optoelectromechanic effects in nanocontacts: Electric-field enhancement and mechanically driven conductance changes

纳米接触中的光机电效应：电场增强和机械驱动的电导变化

基本信息

批准号：
151185874
负责人：
Professorin Dr. Elke Scheer
金额：
--
依托单位：
Arbeitsgruppe Mesoskopische Systeme
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2009
资助国家：
德国
起止时间：
2008-12-31 至 2015-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/151185874?language=en
关键词：
Optoelectromechanic effects nanocontacts Electric field

项目摘要

This project aims at the investigation of nanostructures interacting with pulsed laser irradiation. One aspect is the distribution of electromagnetic fields around nanostructures, another one the influence of these fields on the properties of the nanostructures, in particular the electron transport through atomic-size contacts and nanogaps of controllable size between metallic nanostructures. Since the field enhancement at metallic tips - depending on the polarization of the incident wave - can be very pronounced, a large influence on the current through the junction is to be expected in those regimes where the dc l-V characteristics are nonlinear. A question to be addressed is whether the rectification effect known from ac measurements with nonlinear junctions at low frequencies also persists at optical frequencies. Other possible effects to be studied include the creation of surface plasmons, photo-currents or a strong non-equilibrium energy distribution of the electrons, and optically controlled tunneling currents in nanocontacts. In order to quantify effects of thermal expansion, different sample geometries like suspended nanobridges in the mechanically controllable break-junction geometry as well as nanostructures on membranes and nanogaps of bowtie geometry will be investigated. The expected outcome is a model system to study nano-opto-electromechanic effects and to explore its suitability as a tool for controlling electronic transport by optomechanical drive. This model system with electrically biased nanogaps between plasmonic nanoparticles made with precision of 1-10 nm will be used to investigate the polarization, intensity, and wavelength dependence of the plasmon enhancement factor and its effects on the electron transport in the mechanically controlled gaps. Also, plasmon-mediated photochemical reactions in the volumes with cross-sections of tens-of-nm will be carried out (a case study: photopolymerization).

本项目旨在研究纳米结构与脉冲激光照射的相互作用。一方面是纳米结构周围的电磁场的分布，另一方面是这些场对纳米结构的性质的影响，特别是通过金属纳米结构之间的可控尺寸的原子尺寸接触和纳米间隙的电子传输。由于在金属尖端的场增强-取决于入射波的极化-可以是非常明显的，一个大的影响，通过结的电流是预期在这些制度中的DC的I-V特性是非线性的。要解决的一个问题是整流效应是否已知的交流测量与非线性结在低频率也持续在光学频率。其他有待研究的可能效应包括表面等离子体激元、光电流或电子的强非平衡能量分布的产生，以及纳米接触中的光学控制隧穿电流。为了量化热膨胀的影响，将研究不同的样品几何形状，如机械可控的断裂结几何形状中的悬浮纳米桥以及蝴蝶结几何形状的膜和纳米间隙上的纳米结构。预期的结果是一个模型系统，研究纳米光机电效应，并探讨其适用性作为一种工具，用于控制电子输运的光机驱动器。该模型系统具有以1-10 nm的精度制成的等离子体纳米颗粒之间的电偏置纳米间隙，将用于研究等离子体增强因子的偏振、强度和波长依赖性及其对机械控制间隙中的电子传输的影响。此外，等离子体介导的光化学反应的体积与几十纳米的横截面将进行（一个案例研究：光聚合）。