Matter Adsorbed on Nanoscale Devices

技术摘要这个项目将以沉积在一个、两个或捆绑的单壁碳纳米管上的单层原子或简单分子的形式测量物质的性质和物相。由于已经设计、建造和测试了非常灵敏的单悬吊纳米管和双悬吊纳米管机械振荡器，它在上兆赫兹范围内振动，充当极其灵敏的质量平衡(在几个原子的水平上)，该项目将使用从He同位素到Xe的原子以及有趣的氢、氮和氧分子来测量质量吸附等温线。由于悬浮纳米管表面纯净且质量极低，该项目将精确绘制相界图，测量二维(2D)物质的临界和三临界参数，研究二维到一维(1D)的交叉行为随温度和吸附质量的变化，获得经典和量子力学单分子膜的优秀吸附热值，并研究表面吸附对衬底电子性质的影响，这可能导致新的超灵敏物质特定探测器的制造。对于这些感兴趣的系统，该项目将利用法国格勒诺布尔的设施，通过国际合作测量吸附物的晶体结构和声子谱。参与的研究生和本科生正在接受当代电子、热力学、扫描和散射测量技术的培训，这些技术都适用于纳米技术。非技术摘要：只有一层厚的原子或分子薄膜(据说是“二维”的)在比普通的“三维”物质更低的温度下凝聚和凝固。原子线(极端的“一维”情况)预计不会凝聚或凝固，甚至一直到绝对零度。为了探索这一令人着迷的极限，该项目将以限制在一个或两个单独的单壁碳纳米管表面的单层原子或简单分子的形式测量物质的性质。利用我们已经设计、建造和测试的纳米管机械振荡器作为极其灵敏的质量平衡(它只能检测到表面上的几个原子)，该项目将测量许多不同温度下的质量沉积，原子范围从氦(低质量)到氙气(大质量)，以及氢、氮和氧的分子形式，这是非常有实际意义的。该项目还将研究它们对电子在纳米管中运动的影响，这可能会导致新的、更灵敏和特定于气体的探测器。对于某些系统，该项目还将利用法国格勒诺布尔的设施，通过国际合作测量吸附物的排列和振动光谱。该项目涉及研究生和本科生，他们正在接受广泛温度范围内适用于纳米技术的当代电子、热力学、扫描和散射测量技术的培训。

Technical AbstractThis project will measure the properties and phases of matter in the form of a single layer of atoms or simple molecules deposited on one, two, or bundled single-walled carbon nanotubes. With already designed, constructed and tested very sensitive one- and two-suspended nanotube mechanical oscillators vibrating in the upper megahertz range to act as extremely sensitive mass balances (at the level of a few atoms), this project will measure mass adsorption isotherms using atoms from the He isotopes to Xe, and the interesting molecules of hydrogen, nitrogen and oxygen. Due to the pristine surface and very low mass of the suspended nanotubes, this project will map accurately phase boundaries, measure critical and tri-critical parameters of two-dimensional (2d) matter, study 2d to one-dimensional (1d) crossover behavior as a function of temperature and adsorbed mass, obtain excellent values of heats of adsorption for both classical and quantum mechanical monolayers, and study the effect of surface adsorbates on the electronic properties of the substrate, which may lead to the fabrication of new ultra sensitive matter specific detectors. For those systems of interest, this project will measure the crystalline structure and the phonon spectrum of the adsorbates through an international collaboration using the facilities in Grenoble, France. Graduate and undergraduate students participating are being trained in contemporary electronic, thermodynamic, scanning and scattering measurement techniques, all applicable to nanotechnology. Non Technical Abstract.Films of atoms or molecules just one layer thick (said to be "two-dimensional") condense and solidify at lower temperatures than regular "three-dimensional" matter. Lines of atoms (the extreme "one-dimensional" case) are expected not to condense or solidify even all the way down to absolute zero of temperature. To explore this fascinating limit, this project will measure the properties of matter in the form of a single layer of atoms or simple molecules confined to the surface of one or two individual single-walled carbon nanotubes. With nanotube mechanical oscillators which we have already designed, constructed and tested acting as extremely sensitive mass balances (which can detect just a few atoms on the surface), this project will measure mass deposition at many different temperatures, with atoms ranging from the isotopes of helium (low mass) to xenon (large mass), and the molecular forms of hydrogen, nitrogen and oxygen which are of great practical interest. This project also will study their effect on the electrons moving in the nanotubes, which may lead to new, more sensitive and gas-specific detectors. For certain systems this project will also measure the arrangement and the vibrational spectrum of the adsorbates through an international collaboration using facilities in Grenoble, France.This project involves graduate and undergraduate students who are being trained in contemporary electronic, thermodynamic, scanning and scattering measurement techniques applicable to nanotechnology, over a wide range of temperatures.