Theoretical Study of Nitride Wide Bandgap Semiconductors forElectronic and Optical Applications

本研究将提供几个领域的理论研究，这些领域对新兴的一类由三氮化族组成的宽带隙半导体化合物至关重要。一系列基本性质，包括氮化铝、氮化镓和氮化铟的电子输运和光学性质，将通过第一性原理方法计算。计算电子性质对应变和光学声子畸变的依赖关系将为高温输运建模提供所需的信息。将计算锌闪锌矿和纤锌矿两种形式的光学响应函数和其他光谱信息。氮空位是影响材料质量的一个重要缺陷。本项目将研究由铝和镓组成的ternay合金体系、铟和镓与氮组成的ternay合金体系以及碳化硅与氮化铝的伪二元合金的相应性能。这部分工作将利用适当的统计模型来治疗紊乱。研究了小周期超晶格的光学特性和异质结构的带偏。这项工作预计将对目前正在开发的新型生长技术所产生的材料的表征工作产生重大影响。这将有助于在短波长和高温下工作的光电器件的发展。为了计算一类具有许多应用潜力的新型半导体化合物的性质，将进行计算密集型研究。这些以氮化物为基础的复杂材料，除了具有电子特性外，还具有光学特性。此外，这些都是坚硬的材料，可以在高温下发挥作用。因此，需要在高温下工作的光电器件的应用将受益。

This research will provide theoretical investigations of several areas which are crucial to the emerging class of wide bandgap semiconductor compounds comprised of group three-nitrides. A range of basic properties, including the electronic transport and optical properties of aluminum nitride, gallium nitride and indium nitride, will be calculated by means of first-principles methods. Calculations of the dependence of the electronic properties on strain and optical phonon distortions will provide information needed in the modeling of high temperature transport. The optical response functions and other spectroscopic information will be calculated for both the zincblende and the wurtzite forms. The nitrogen vacancy, an important defect for the quality of the material, will be investigated. The project will study the corresponding properties for ternay alloy systems composed of aluminum and gallium, and indium and gallium with nitrogen, as well as the pseudo-binary alloy of silicon carbide with aluminum nitride. This part of the work will make use of appropriate statistical models in the treatment of disorder. The optical properties of small period superlattices and the band-offsets of heterostructures will be studied. The work is expected to have a significant impact on the characterization efforts of material produced by novel growth techniques currently under development. This will assist the development of opto-electronic devices operating at short wavelengths and at high temperatures. %%% Computationally intensive research will be conducted in order to calculate the properties of a new class of semiconductor compounds which have the potential for many applications. These complex materials, which are based on the nitrides, are particularly useful for their optical properties in addition to their electronic ones. Also, these are hard materials which can function at high temperatures. Thus, applications requiring opto-electronic devices operating at high temperatures will benefit.