Study of Carrier Transport and Impact Ionization in GaN/AlGaN

9408479 Ruden这项工作的目的是提供第一个全面的理论研究的电子和空穴传输GaN和AlGaN块体和多量子阱结构的具体目标，确定电子和空穴的碰撞电离率在这些系统。 从GaN/AlGaN的输运性质的知识，可以评估的p-n结GaN/AlGaN低噪声紫外雪崩探测器的开发的可行性。 到目前为止，还没有紧凑的，低电压的，固态紫外光探测器存在，为了判断GaN/AlGaN雪崩光电二极管的效用，有必要知道这些材料中的碰撞电离率。 在这项工作中，电子和空穴的碰撞电离率将在理论上确定使用合奏蒙特卡罗模拟，其中包括从赝势方法计算的导带和价带的全部细节。 一个新的配方的影响电离过渡率将被包括在蒙特卡洛模拟器，考虑到k依赖的过渡率提供第一原则确定的载流子电离率。 使用这种技术，电子和空穴的电离率将计算在体GaN，AlGaN和相关的多量子阱和超晶格结构。 计算结果将提供用于紫外探测的p-n结APD的GaN/AlGaN的第一个评估。 此外，本研究中使用的模拟工具的改进将对其他器械的建模产生重大影响。 一些可能的设备，其设计和优化，可以帮助发展的建议模拟器是低噪声，高增益的光电探测器的高数据速率通信，新的APD设计的波长检测从紫外线到红外线，和超低噪声IMPATT二极管。 这项研究是格鲁吉亚技术研究所和明尼苏达大学的研究人员合作进行的。 ***

9408479 Ruden The purpose of this work is to provide the first theoretical comprehensive study of electron and hole transport in GaN and ALGaN bulk and multiquantum well structures with the specific goal of determining the electron and hole impact ionization rates in these systems. From the knowledge of the transport properties of GaN/ALGaN obtained, the feasibility of developing a p-n junction GaN/AlGaN low-noise ultraviolet avalanching detector can be assessed. To date no compact, low-voltage, solid-state ultraviolet photodetector exists, In order to judge the utility of a GaN/AlGaN avalanche photodiode it is necessary to know the impact ionization rates in these materials. In this work, the electron and hole impact ionization rates will be theoretically determined using ensemble Monte Carlo simulations which include the full details of the conduction and valence bands calculated numerically from the pseudopotential method. A new formulation of the impact ionization transition rates will be included in the Monte Carlo simulators which takes into account the k-dependence of the transition rate providing a first principles determination of the carrier ionization rates. Using this technique, the electron and hole ionization rates will be calculated in bulk GaN, AlGaN and in related multiquantum well and superlattice structures. The calculated results will provide the first assessment of GaN/AlGaN for use in p-n junction APDs for ultraviolet detection. In addition, the refinement of the simulation tools used in this study will have significant impact on modeling other devices. Some possible devices whose design and optimization can be aided by the development of the proposed simulators are low noise, high gain photodetectors for high data rate communications, new APD designs for detection of wavelenghts from the ultraviolet to the infrared, and ultra-low noise IMPATT diodes. This study is a collaboration between researchers at Georgia Institute of Techology and University of Minnesota. ***