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

小行星9321826 技术摘要：本研究将集中在宽带隙硒化锌和III-V族氮化物（氮化镓，氮化铟，氮化铝）的表面和金属界面的结构，化学和电子特性。 将测试这些材料的肖特基势垒模型的有效性开发的窄间隙半导体。 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形成金属-半导体势垒中的作用将被确定。 该项目还将调查氮化铝表面的负电子亲和力的发生。 形成的金属锌硒化物和金属氮化物的障碍将被调查，以建立这些材料的肖特基势垒的依赖的限制。 将研究界面的热稳定性，这对高温应用（氮化镓）尤其重要。 这将包括对扩散和化学反应障碍的研究（例如，例如，在一个实施例中，氮化钛-氮化镓）。 最后，将讨论制作这些p掺杂半导体欧姆接触的难题. 这些接触对于发光器件的发展至关重要。 将研究两种技术：p型氮化镓的高p型掺杂和大功函数金属（铂）的组合，以及p型硒化锌上的高电负性聚合物和金属（聚硫氮化物）接触。 非技术摘要：该项目将研究两种重要类型半导体的界面的结构，化学和电子特性：硒化锌和III-V族氮化物（氮化镓，氮化铟和氮化铝），它们在光电子学（II-VI的蓝绿色发射，氮化物的蓝紫外线）和高温电子学（氮化物）中有应用。 拟议的工作将开始建立这些材料的界面特性的坚实的理解，为未来的技术发展，以及测试的有效性接口的概念和金属-半导体势垒模型开发的间隙较窄的半导体。 欧姆接触的形成将被研究，因为这些对于高性能、可靠的发光器件的操作是至关重要的。 例如，这些接触的化学稳定性将通过制备扩散阻挡层来调节，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. ***