Atomic and Electronic Properties of Surfaces and Interfaces of Wide Band Gap Compound Semiconductors

技术摘要：本研究将重点研究宽带隙硒化锌和III-V型氮化物（氮化镓、氮化铟、氮化铝）表面和金属界面的结构、化学和电子性能。为窄间隙半导体开发的肖特基势垒模型的有效性将在这些材料上进行测试。电子表面态的性质，它们对表面带弯曲的影响以及它们在金属半导体势垒形成中的作用将被确定。该项目还将研究氮化铝表面负电子亲和的发生。为了确定肖特基势垒依赖于这些材料的极限，将研究金属-硒化锌和金属-氮化物势垒的形成。界面的热稳定性，尤其重要的高温应用（氮化镓）将进行研究。这将包括寻找扩散和化学反应屏障（例如，钛-氮化镓）。最后，将讨论如何与这些p掺杂半导体进行欧姆接触的难题。这些接触对发光器件的发展至关重要。将研究两种技术：高p掺杂和大功函数金属（铂）在p-氮化镓上的结合，以及高电负性聚合物和金属（聚氮化硫）在p-硒化锌上的接触。非技术摘要：本项目将研究两种重要类型的半导体：硒化锌和III-V族氮化物（氮化镓、氮化铟和氮化铝）的界面结构、化学和电子特性，这两种半导体在光电子学（II-VIs的绿蓝色发射，氮化物的蓝紫外线发射）和高温电子学（氮化物）中有应用。拟议的工作将开始为这些材料建立对其界面特性的坚实理解，以用于未来的技术发展，以及测试为窄间隙半导体开发的界面概念和金属-半导体势垒模型的有效性。欧姆接触的形成将被研究，因为这些对高性能、可靠的发光器件的操作至关重要。例如，这些接触的化学稳定性将通过制备扩散屏障来调节，这将导致这些材料的界面工程。＊＊＊

9321826 Kahn Technical abstract: This study will focus on the structural, chemical, and electronic properties of surfaces and metal interfaces of wide band gap zinc-selenide and III-V nitrides (gallium nitride, indium nitride, aluminum nitride). The validity of the Schottky barrier models developed for narrower gap semiconductors will be tested for these materials. The nature of electronic surface states, their impact on the surface band bending and their role in the formation of metal-semiconductor barriers will be determined. The project will also investigate the occurrence of negative electron affinity which has been reported for aluminum nitride surfaces. Formation of metal-zinc-selenide and metal-nitride barriers will be investigated in order to establish the limits of the dependence of Schottky barriers on these materials. The thermal stability of interfaces, especially important for high temperature applications (gallium nitride) will be investigated. This will include a search for diffusion and chemical reaction barriers (e. g., titanium-gallium nitride). Finally, the difficult problem of making ohmic contacts to these p- doped semiconductors will be addressed. These contacts are crucial for the development of light emitting devices. Two techniques will be studied: combination of high p-doping and large work function metal (platinum) for p-gallium nitride, and high electronegativity polymeric and metallic (poly sulfur nitride) contact on p-zinc- selenide. Non-technical abstract: This project will investigate the structural, chemical and electronic properties of interfaces of two important types of semiconductors: zinc selenide and the Group III-V nitrides (gallium nitride, indium nitride, and aluminum nitride), which have applications in optoelectronics (emission in the green-blue for the II-VIs, blue-ultraviolet for the nitrides) and high temperature electronics (nitrides). The proposed work will begin to establish for these materials a solid understanding of their interface properties for future technological developments, as well as to test the validity of interface concepts and metal-semiconductor barrier models developed for narrower gap semiconductors. The formation of ohmic contacts will be investigated, since these are crucial for the operation of high- performance, reliable, light-emitting devices. For example the chemical stability of these contacts will be modulated via preparation of diffusion barriers which should lead to interface engineering of these materials. ***