SGER: Polar-Opitcal-Phonon Enhancement of Nonlinear Effects at the Shottky Barrier Interface

0096519盖尔蒙特随着高频器件进一步扩展到太赫兹（THz）范围，电子物理将首次受到极性光学声子共振（POP）的影响，这种共振通常位于1 THz以上。在此频率范围内，所有异极材料的介电常数的色散都不能忽略。在POP频率下，介电常数具有奇异性，该奇异性影响和扰动异质结构势垒器件内的所有物理过程。因此，THz电子学的新兴领域需要发展新的物理理论来分析POP频率附近的异质结界面，在过去的两年中，GaAs势垒异质结耗尽层内POP效应的新理论已经被提出[1-2]。这一物理现象是基于电子材料在极化光-声子共振频率附近的复介电常数的急剧变化，这种变化导致耗尽型异质结构的高度非线性行为，而这种简化的理论迄今只考虑了正向偏置条件，忽略了中性层和外部寄生效应，它预测了很强的POP影响。具体而言，它预测，存在于电子depletedregion内的持久性有机污染物的影响附近的半导体谐振频率的势垒充电动力学，直接修改的势垒，扰动的空间依赖性的耗尽区内的电场和强烈改变与异质结电流的非线性。这种强烈且高度局域化的频率空间现象对所有利用非线性电子输运效应的基于极性半导体的异质结构器件具有广泛的影响。这个探索性研究项目的目标是开发一种新的定量和基于物理的模型，用于研究高频半导体界面的动力学。特别地，提出了研究正向和反向偏置异质结构的非线性行为的研究调查。该物理模型将与电路嵌入算法相结合，以进行基于异质结的高频器件在实际情况下运行的动态行为的计算机模拟。这项工作还将考虑由新材料系统构建的界面的物理操作，这些新材料系统可用于释放具有良好势垒高度和非常低的谐振频率（~600 GHz）的肖特基界面。这些特定的科学研究为基于晶闸管的电子器件的功能和性能引入新的自由度带来了巨大的希望。例如，增强异质结结构的非线性的可能性，以及因此的固有谐波产生能力，将对在太赫兹频率下工作的高效率谐波倍增器源的研究产生深远的影响。

0096519GelmontAs high-frequency devices are extended farther into the terahertz (THz) regime, theelectron physics will, for the first time, be impacted by polar optical phonon resonance(POP) that typically lies above 1 THz. In this frequency region, the dispersion of thepermittivity in all heteropolar materials can not be neglected. At the POP frequency, thepermittivity has a singularity that influences and perturbs all physical processes withinheterostructure barrier devices. Thus, the emerging area of THz electronics requires thedevelopment of new physical theories for the analysis of the heterojunction interface inthe vicinity of the POP frequencies.In the last two years, the new theory of POP effects within depletion layers of GaAsbarrier heterostructures has been proposed [1-2]. This physical phenomenon is based upondramatic change in complex permittivity of electronic material near the polaroptical-phonon resonance frequency which cause highly nonlinear behavior of depletedheterostructure modified by the interaction between the lattice and the electric field.While this simplified theory to date has considered only forward bias conditions and hasignored neutral layer and external parasitic effects, it predicts a strong POPinfluence. Specifically, it predicts that the POPs present within the electron-depletedregion influence the barrier charging dynamics near the semiconductor resonant frequency, directly modify the potential barrier, perturb the spatial dependence of the electric field within the depletion-region and strongly alter the nonlinearity associated with the heterostructure current. This strong and highly-localized frequency-space phenomenon has broad implications to all polar-semiconductor-based heterostructure devices that utilize nonlinear electron transport effects.The goals of this exploratory research project is to develop a new quantitative andphysics-based model for investigating the high frequency dynamics of semiconductorinterfaces. In particular, a research investigation is proposed to study the nonlinearbehavior of forward and reversed bias heterostructures. The physical model will beintegrated with a circuit-embedding algorithm to conduct computer simulation of dynamicbehavior of heterojunction based high frequency devices operating within realisticsituations. This work will also consider the physical operation of interfaces that areconstructed from novel materials systems which can be used to release Schottky interfaceswith good barriers heights and very low resonance frequencies (~600 GHz).These particular scientific investigations hold great promise for introducing new degreesof freedom into the functionality and performance of semiconductor-based electronicdevices. For example, the possibility of enhancing the nonlinearity, and therefore theinnate harmonic generation capacity, of heterojunction structures would have a profoundimpact on the search for high-efficiency harmonic multiplier sources operating at THzfrequencies.