Beating Effect of Traveling Electron Waves bv Terahertz Electromagnetic Wave and Its Application to Ultra-High Speed Three-Terminal Devices

在这个项目中，为了实现我们提出的一种利用电子波的光子辅助跃迁和拍频来实现超高频放大器的新型电子器件，我们(I)建立了绝缘体/半导体异质结的外延生长，并将其应用于所提出的器件的共振隧穿结构，(Ii)详细观察了作为所提器件的原理之一的光子辅助隧穿。对于外延生长，我们选择了具有大带偏的CaF_2/Si和CaF_2/CDF_2异质结，并利用电离束外延技术建立了共振隧穿结构的生长条件。采用选择性生长的方法，在SiO_2掩模的硅衬底上形成几百纳米尺寸的窗口，从而优化和大大提高了外延层的质量。HISH…共振隧穿二极管为了观察光子辅助隧穿效应，我们制作了与贴片天线集成的小面积GaInAs/InAlAs三势垒共振隧穿二极管，并对其进行了太赫兹电磁波辐照。通过对天线结构的优化，大大降低了天线的损耗，从而实现了大入射功率下清晰的光子辅助隧道效应。用多光子受激发射和吸收过程的光子辅助隧穿很好地解释了观测结果，从观测到的受激发射率推导出太赫兹光增益。利用这些结果，我们对所提出的三端器件的放大特性进行了理论分析，表明功率放大到几太赫兹是可能的。还针对这些特性设计了必要的结构。较少

In this project, aiming at the realization of a novel electron device we proposed for a possibility of ultra-high frequency amplifier utilizing the photon-assisted transition and beating of electron waves, we have done (i) establishment of the epitaxial growth of insulator/semiconductor heterostructures and thier application to resonant tunneling structure which is a part of the proposed device, and (ii) detailed observation of the photon-assisted tunneling which is one of the principles of the proposed device.For the epitaxial growth, we chose CaF_2/Si and CaF_2/CdF_2 heterostructures with large band offsets, and established the growth condition of resonant tunneling structure with the ionization beam epitaxial technique. The quality of the epitaxial layers was then optimized and greatly improved by a selective growth method in which the epitaxial layers were formed in windows with a few hundred-nanometer size made on Si substrates with SiO_2 masks. Resonant tunneling diodes with hish … More reproducibility and large peak-to-valley ratio, at least 10, in the negative differential resistance were obtained at room temperature.For the observation of the photon-assisted tunneling effect, we fabricated small area GaInAs/InAlAs triple-barrier resonant tunneling diodes integrated with patch antennas, and irradiated terahertz electromagnetic wave onto them. The antenna loss was considerably reduced by an optimized structure, and thus, clear photon-assisted tunneling with large incident power was achieved. The observed results were well explained by the photon-assisted tunneling with multi-photon process of stimulated emission and absorption The terahertz optical gain was deduced from the observed stimulated emission rate. Using these results, we performed theoretical analysis of amplification characteristics of the proposed three-terminal device, and showed that power amplification up to several terahertz is possible. Necessary structures for these characteristics were also designed. Less