Fabrication and Electrical Characterization of Atomic-Scale Wires

9623355史密斯这项研究的最终目标是制造原子尺度的导线，甚至是直径一个原子的导线，并在其上进行低温电学测量。这些金属丝将通过自然生长和扫描隧道显微镜(STM)的图案化组合而成。早期的实验将包括对以前没有被STM研究的金属链形成系统的成像和链稳定性的研究。将使用阶跃边缘蒸发或STM化学气相沉积来制作连接链条和宏观接触的中等尺度接触探头。这一阶段的实验将检查这些中等规模的焊盘对原子链的任何破坏性影响，以及焊盘和原子链之间的任何电接触问题。一旦样品制成，它将被转移到同一超高真空室中的低温阶段，并将测量其电学性质。作为上述实验的前奏，我们将研究杂散电容对单电子隧穿的影响。这个基础研究项目将考察在制造原子级电子电路方面的一些明显挑战。我们的最终目标是制造所有此类电路中最简单的一种，原子尺度的导线(甚至可能只有一个原子直径)，并对其进行低温电学测量，以探索量子力学效应。我们将结合使用半导体衬底上金属的自然有序、扫描隧道显微镜的图案化和“阶梯边缘蒸发”技术来制造导线，阶梯边缘蒸发是一种使用衬底中的小步骤来创建纳米级结构的技术。有几个明显的挑战。对于大多数材料来说，导线内导电所需的电子似乎会被产生导线的衬底吸走。电线和宏观世界之间的电连接的建立可能会扰乱电线，或者电线可能会被热波动扰乱。导线和宏观触点之间的电接触可能会被证明是困难的。然而，我们相信，这些挑战中的每一个都是可以应对的，并提出了几项有希望的战略。***

9623355 Smith The ultimate goals of this research are to fabricate atomic- scale wires, perhaps even one atom in diameter, and to make low- temperature electrical measurements on them. The wires will be created by a combination of natural growth and patterning with the scanning tunneling microscope (STM). Early experiments will include imaging of a metal-chain- forming system not previously studied by STM and studies of chain stability. Intermediate-scale contact probes to bridge between the chains and macroscopic contacts will be made using either step-edge evaporation or STM chemical vapor deposition. Experiments in this phase will examine any disruptive effects of these intermediate-scale pads on the atomic chains, and also any problems with electrical contact between the pads and the chains. Once a sample is made, it will be transferred to a low-temperature stage within the same ultrahigh vacuum chamber, and its electrical properties will be measured. As a prelude to all the above experiments, a study of the effects of stray capacitance on single electron tunneling (SET) will be performed. %%% This basic research project will examine some of the apparent challenges in creating atomic-scale electronic circuits. Our ultimate goals are to make the simplest of all such circuits, an atomic-scale wire (perhaps even one atom in diameter), and to perform low-temperature electrical measurements on it to explore quantum mechanical effects. We will make the wire using a combination of natural ordering of metals on semiconductor substrates, patterning with the scanning tunneling microscope, and "step-edge evaporation", a technique which uses small steps in the substrate to create nanometer-scale structures. There are several apparent challenges . For most materials, it appears that the electrons needed for electrical conduction within the wire would be sucked away by the substrate on which the wires are created. The creation of electrical connections betw een the wires and the macroscopic world may disrupt the wires, or the wires might be disrupted by thermal fluctuations. Electrical contact between the wires and the macroscopic contacts may prove difficult. However, we are confident that each of these challenges can be met, and suggest several promising strategies. ***