| 报告题目 | Polaronic transport and current blockades in epitaxial silicide nanowires and nanowire arrays |
| 报告人 | Prof. Hanno H. Weitering |
| 报告人单位 | Department of Physics and Astronomy, University of Tennessee & Materials Science and Technology Division, Oak Ridge National Laboratory, USA |
| 报告时间 | 2013-07-11 |
| 报告地点 | 合肥微尺度物质科学国家实验室九楼会议室 |
| 主办单位 | 合肥微尺度物质科学国家实验室 |
| 报告介绍 |
Quantum transport is at the heart of nanoscience and marries a fundamental law of nature, quantum mechanics, with applied electrical engineering and emerging materials technologies. Ultimately, nanoscale electronic devices will contain networks of wires whose cross sections will be so small as to represent quasi one-dimensional conductors with novel transport properties. Among the many intriguing nanowire systems synthesized in recent years, epitaxial metal-silicide nanowires may be the most practical electrical interconnects because of their low resistivity, stable Schottky barriers, and compatibility with the scalable silicon platform. In this talk, I will discuss some of the idiosyncrasies of quasi one-dimensional electron systems and present a detailed analysis of the electronic structure and electrical transport properties of some of the thinnest epitaxial YSi2 nanowires, measured using a four-tip scanning tunneling microscope. Conduction through individual nanowires follows an inverse Arrhenius behavior indicative of thermally-assisted tunneling of small polarons between defect centers. A scaling analysis of the I-V data produces microscopic parameters such as the phonon frequency, polaron shift, and the number of trapping centers. Quantitative analysis of individual wire resistances, probe resistances, and negative differential resistances of nanowire networks furthermore indicates significant electronic interwire coupling below 150 K. The long-range coupling mechanism involves the dielectric polarization of the substrate, inducing current blockades in neighboring conduction channels. This study demonstrates the feasibility of nanoscale circuit analysis using four-point probe measurements, but also points towards the need for utmost control of atomic-scale defects in the electrical and materials engineering of novel nano-architectures.
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