Electron Transport in Semiconductor Nanostructures

w：\awards\awards96\*.doc 9802242 Westerpyruvate 这个实验研究项目研究电子在隧道耦合量子点中的行为。用一个恰当的类比，这样的系统可以被视为人工分子，单个点被视为原子。这些系统中电子的基本特性;电子如何在点之间共享，共享电子状态的能量，以及电子如何通过耦合点电路移动;是感兴趣的。 具体的测量包括小的隧道耦合点（小于100个电子每点）的库仑阻塞光谱;在量子霍尔制度的隧道耦合点的库仑阻塞光谱;通过单量子点与部分开放的铅运输，预计将显示有趣的许多身体效应;和运输通过开放的电子波谐振器。点样品是在哈佛使用电子束光刻在加州大学圣巴巴拉通过分子束外延生长的GaAs/AlGaAs晶片上制作的。该研究计划是跨学科的，涉及一名或多名研究生，他们接受了良好的培训，为工业，政府实验室或学术界的职业生涯做准备。 %本实验研究项目研究通过量子力学电子隧穿耦合的半导体量子点中的电子行为。用一个恰当的类比，这样的系统可以被视为人工分子，单个点被视为原子。“量子点”是GaAs/AlGaAs晶片表面的一个小区域，类似于先进微电子器件中使用的量子点。一个二维的电子气产生的表面下的整个晶圆，然后微型 电极 沉积 使用 电子 光束光刻可以隔离一个微小的区域， 电子， 叫做qu antum 圆圆. 的 这些系统中电子的基本特性;电子如何在点之间共享，共享电子状态的能量，以及电子如何通过耦合的点电路移动，都是感兴趣的。 具体的测量包括小的隧道耦合点（小于100个电子每点）的库仑阻塞光谱;在量子霍尔制度的隧道耦合点的库仑阻塞光谱;通过单量子点与部分开放的铅运输，预计将显示有趣的许多身体效应;和运输通过开放的电子波谐振器。点样品是在哈佛使用电子束光刻在加州大学圣巴巴拉通过分子束外延生长的GaAs/AlGaAs晶片上制作的。这项研究与未来的电子产品有关，其中设备将接近大分子的尺寸。在这种尺度下，量子力学甚至在室温下也很重要。量子现象提供了新的计算方法，从超密度单电子存储器到量子计算机，预计速度将呈指数级增长。 的 研究 这里 地址 的 量子力学电子的基本特性 国 和隧道耦合半导体纳米结构中的电子传输作为这些可能应用的第一步。该研究计划是跨学科的，涉及一名或多名研究生，他们接受了良好的培训，为工业，政府实验室或学术界的职业生涯做准备。 ***

w:\awards\awards96\*.doc 9802242 Westervelt This experimental research project investigates the behavior of electrons in tunnel-coupled quantum dots. In an apt analogy, such systems can be regarded as artificial molecules, the individual dots being considered as atoms. The fundamental characteristics of electrons in these systems; how electrons are shared between dots, the energy of shared electron states, and how electrons move through coupled dot circuits; are of interest. Specific measurements include Coulomb blockade spectroscopy of small tunnel-coupled dots (less than 100 electrons per dot); Coulomb blockade spectroscopy of tunnel-coupled dots in the quantum Hall regime; transport through single quantum dots with partially open leads, predicted to show interesting many body effects; and transport through open electron wave resonators. Dot samples are made at Harvard using electron beam lithography on GaAs/AlGaAs wafers grown via molecular beam epitaxy at Univ. California Santa Barbara. This research program is interdisciplinary in nature and involves one or more graduate students, who receive excellent training in preparation for careers in industry, government laboratories or academia. %%% This experimental research project investigates the behavior of electrons in semiconductor quantum dots coupled by quantum- mechanical electron tunneling. In an apt analogy, such systems can be regarded as artificial molecules, the individual dots being considered as atoms. The "quantum dot" is a small region in the surface of a GaAs/AlGaAs wafer, similar to those used in advanced microelectronic devices. A two-dimensional electron gas is produced just below the surface of the entire wafer, and then miniature electrodes are deposited using electron beam lithography which can isolate a tiny region containing as few as 100 electrons, called a qu antum dot. The fundamental characteristics of electrons in these systems; how electrons are shared between dots, the energy of shared electron states, and how electrons move through coupled dot circuits, are of interest. Specific measurements include Coulomb blockade spectroscopy of small tunnel-coupled dots (less than 100 electrons per dot); Coulomb blockade spectroscopy of tunnel-coupled dots in the quantum Hall regime; transport through single quantum dots with partially open leads, predicted to show interesting many body effects; and transport through open electron wave resonators. Dot samples are made at Harvard using electron beam lithography on GaAs/AlGaAs wafers grown via molecular beam epitaxy at Univ. California Santa Barbara. The research is relevant to future electronics in which devices will approach the size of large molecules. At this size scale quantum mechanics is important even at room temperature. Quantum phenomena offer new approaches to computation ranging from ultra dense single-electron memories to quantum computers projected to give an exponential increase in speed. The research here addresses the fundamental characteristics of quantum mechanical electron states and electron transport in tunnel-coupled semiconductor nanostructures as a first step toward these possible applications. This research program is interdisciplinary in nature and involves one or more graduate students, who receive excellent training in preparation for careers in industry, government laboratories or academia. ***