Single-electron-level ballistic transport devices

该项目涉及开发一类新的电子器件，提供飞秒渡越时间在室温空气环境中的单电子水平上运行。 所提出的器件结构的工作原理涉及电子在纳米级空隙通道中的弹道传输，所述纳米级空隙通道将形成在金属氧化物半导体结构的氧化物层中。 金属-氧化物-半导体结构将被驱动进入击穿操作状态（即，电场被设置为大于氧化物击穿场强），以便在氧化物层中形成纳米级泄漏通道。 氧化物厚度（沟道长度）将被设计为小于空气中的平均自由碰撞路径，使得由此形成的空隙沟道基本上用作纳米级真空电子器件的介质。 在这种空气中的准真空模式操作中，电子的弹道传输预计将在宽电压范围内表现出空间电荷限制电流，遵循Child-Langmuir [电压]3/2幂定律。 电子渡越时间计算为10-100飞秒，可能提供超过10-100太赫兹的操作。 纳米通道中的空间电荷限制输运预计是单电子水平的。 飞秒渡越时间的单电子输运可以产生~微安量级的沟道电流，为室温下的高信噪比光电器件提供了潜在的可能。 本研究的目的是发展一个基本的理解发生在本地化的纳米通道的电荷传输过程及其应用到超快（下至飞秒级）photodetector.Intellectual MeritElectron输运在纳米尺度的有限空间是一个基本的过程，其理解是至关重要的，在开发先进的电子/光电子器件。 所提出的纳米电子结构（在硅金属氧化物半导体结构的氧化物中形成的~10 nm尺度的空隙通道）提供了真空传输电子的优势，但在其操作中不需要任何真空介质。 了解纳米通道形成的机制及其极端的传输特性（~10飞秒传输时间）有望为纳米电子学/光电子学的科学和技术带来重大进步。 这项研究解决了科学和工程的挑战，在推进硅金属氧化物半导体为基础的结构，成为一个新的器件技术，提供了一个伟大的承诺，最终操作在单电子，单光子level.Broader ImpactsThis研究将作出重大影响，如电信，信息处理，仪器/计量和国防等各个领域。 该项目的多学科性质将为培训未来的科学家和工程师提供一个教育范例，用于纳米电子学，纳米光子学和纳米级真空电子学的新兴领域。 来自代表性不足群体的学生将在各个层次和范围招募，如研究生研究（硕士和博士学位），本科研究经验和高中生暑期充实计划。 这些学生将获得动手经验，通过各种仪器可在纳米制造和表征设施（在PI的机构的用户设施）从PI的实验室指导研究生研究人员。

This project deals with developing a new class of electronic devices that offer femtosecond transit time operating at a single-electron level in room-temperature air ambient. The operating principle of the proposed device structure involves ballistic transport of electrons in a nanoscale void channel that will be formed in the oxide layer of a metal-oxide-semiconductor structure. A metal-oxide-semiconductor structure will be driven into a breakdown regime of operation (that is, the electric field is set greater than the oxide breakdown field strength) in order to form nanoscale leakage channels in the oxide layer. The oxide thickness (channel length) will be designed to be smaller than the mean free collision path in air so that the thus-formed void channels essentially serve as a medium for nanoscale vacuum electronics. In this quasi-vacuum-mode operation in air, the ballistic transport of electrons is expected to demonstrate a space-charge-limited current over a broad range of voltage, following the Child-Langmuir's [voltage]3/2 power law. The electron transit time is calculated to be 10-100 femtosecond, potentially offering over 10-100 terahertz operation. The space-charge-limited transport in the nano-channel is expected to be of single electron level. The single-electron transport with femtosecond transit time can result in the channel current of ~microampere level, potentially offering high signal-to-noise ratio operation of optoelectronic devices at room temperature. This study aims at developing a fundamental understanding of the charge transport process occurring in the localized nanochannels and its application to ultrafast (down to femtosecond level) photodetection.Intellectual MeritElectron transport in a nanometer-scale-confined space is a fundamental process, whose understanding is critically important in developing advanced electronic/optoelectronic devices. The proposed nanoelectronic structure (~10-nm-scale void channels formed in the oxide of a silicon metal-oxide-semiconductor structure) offers the advantage of vacuum in transporting electrons, but does not require any vacuum medium in its operation. Understanding the mechanisms of nanochannel formation and their extreme transport properties (~10 femtosecond transit time) is expected to bring a major advancement to the science and technology of nanoscale electronics/optoelectronics. This study addresses the scientific and engineering challenges in advancing the silicon-metal-oxide-semiconductor-based structure into a new device technology that offers a great promise for ultimate operation at single-electron, single-photon level.Broader ImpactsThis study will make major impacts on various fields such as telecommunications, information processing, instrumentation/metrology, and defense. The multidisciplinary nature of this project will provide an educational paradigm for training future scientists and engineers for the emerging fields of nanoelectronics, nanophotonics and nanoscale vacuum electronics. Students from underrepresented groups will be recruited at various levels and scopes such as graduate research (masters and doctoral degrees), undergraduate research experience, and summer enrichment programs for high school students. These students will gain hands-on-experience through a variety of instrumentation available at the Nanoscale Fabrication and Characterization Facility (a user facility at the PI's institution) mentored by graduate student researchers from the PI's lab.