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

9321826卡恩技术摘要：这项研究将集中在宽带隙硒化锌和III-V氮化物(氮化镓、氮化铟、氮化铝)的表面和金属界面的结构、化学和电子性质。为窄禁带半导体开发的肖特基势垒模型的有效性将针对这些材料进行测试。将确定电子表面态的性质，它们对表面能带弯曲的影响，以及它们在金属-半导体势垒形成中的作用。该项目还将调查已报道的氮化铝表面的负电子亲和力的发生。为了确定肖特基势垒依赖于这些材料的极限，将对金属-锌-硒和金属-氮化物势垒的形成进行研究。将研究界面的热稳定性，特别是高温应用(氮化镓)的热稳定性。这将包括寻找扩散和化学反应障碍(例如，钛-氮化镓)。最后，将解决与这些p掺杂半导体进行欧姆接触的难题。这些触点对发光设备的发展至关重要。将研究两种技术：高磷掺杂和大功函数金属(铂)相结合的p-氮化镓，以及高电负性聚合物和金属(多硫氮化物)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半导体的界面结构、化学和电学性质：亚硒化锌和III-V族氮化物(氮化镓、氮化铟和氮化铝)，这两种半导体在光电子学(发射蓝绿光的II-VIS，发射蓝紫外光的氮化物)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未来技术发展的界面性质的坚实理解，并测试为较窄禁带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，因为这对高性能、可靠的发光设备的运行至关重要。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. ***