Electron Transport in Semiconductor Nanostructures

半导体纳米结构中的电子传输

• 批准号: 9802242
• 负责人: Robert Westervelt
• 金额: $ 27万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-15 至 2001-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9802242&HistoricalAwards=false
• 关键词: Electron; Transport; Semiconductor; Nanostructures

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. ***

w:\awards\awards96\*.doc 9802242 Westervelt 该实验研究项目研究电子在隧道耦合量子点中的行为。打个恰当的比方，这样的系统可以被视为人造分子，各个点被视为原子。这些系统中电子的基本特征；电子如何在点之间共享、共享电子态的能量以及电子如何通过耦合点电路移动；很感兴趣。 具体测量包括小隧道耦合点（每个点少于 100 个电子）的库仑阻塞光谱； 量子霍尔体系中隧道耦合点的库仑阻塞光谱；通过具有部分开放引线的单个量子点进行传输，预计会显示出许多有趣的身体效应； 并通过开放式电子波谐振器进行传输。点样本是在哈佛使用电子束光刻技术在大学通过分子束外延生长的 GaAs/AlGaAs 晶圆上制作的。加利福尼亚州圣巴巴拉。该研究项目本质上是跨学科的，涉及一名或多名研究生，他们接受了良好的培训，为在工业界、政府实验室或学术界的职业生涯做好准备。 %%% 该实验研究项目研究通过量子力学电子隧道耦合的半导体量子点中的电子行为。打个恰当的比方，这样的系统可以被视为人造分子，各个点被视为原子。 “量子点”是 GaAs/AlGaAs 晶圆表面的一个小区域，类似于先进微电子器件中使用的量子点。在整个晶圆表面下方产生二维电子气，然后使用电子束光刻沉积微型电极，可以隔离包含少至 100 个电子的微小区域，称为量子点。 这些系统中电子的基本特征；人们感兴趣的是电子如何在点之间共享、共享电子态的能量以及电子如何通过耦合点电路移动。 具体测量包括小隧道耦合点（每个点少于 100 个电子）的库仑阻塞光谱； 量子霍尔体系中隧道耦合点的库仑阻塞光谱；通过具有部分开放引线的单个量子点进行传输，预计会显示出许多有趣的身体效应；并通过开放式电子波谐振器进行传输。点样本是在哈佛使用电子束光刻技术在大学通过分子束外延生长的 GaAs/AlGaAs 晶圆上制作的。 加利福尼亚州圣巴巴拉。这项研究与未来的电子产品相关，未来电子产品的尺寸将接近大分子。在这种尺寸下，量子力学即使在室温下也很重要。量子现象提供了新的计算方法，从超密集单电子存储器到预计速度呈指数级增长的量子计算机。 这里的研究解决了隧道耦合半导体纳米结构中量子力学电子态和电子传输的基本特征，作为迈向这些可能应用的第一步。该研究项目本质上是跨学科的，涉及一名或多名研究生，他们接受了良好的培训，为在工业界、政府实验室或学术界的职业生涯做好准备。 ***