Synchrotron Radiation Spectroscopic Study of Surface and Bulk Electronic Structure of Wide Band Gap Semiconductors

宽带隙氮化物半导体因其在光电子学、高温和自旋电子器件中的潜在应用而成为人们密切关注的焦点。然而，我们对这些材料的基本物理的理解落后于我们用它们制造电子设备的能力。这一个人研究人员奖支持一个项目，该项目研究清洁和吸附覆盖的氮化物半导体的电子结构。其目的是研究氮化物半导体合金的体电子结构和表面电子结构，以了解其基本的电子性质；研究气体在表征良好的氮化物表面上的吸附，以了解其化学反应、钝化以及无机和有机覆盖层的生长和稳定性；最后研究模型磁性半导体(如GaMnN)的电子结构。该项目将使学生和博士后研究助理接触到国家用户设施的高度协作的研究环境，从而对他们的教育产生重大影响。他们将学习新型半导体材料的物理学，以及同步辐射光谱仪在研究中的应用。这是一项雄心勃勃的计划，旨在对宽带隙半导体的表面和体电子结构进行最终测量。该项目由美国国家科学基金会材料研究部和陆军研究组织物理部共同资助。一类重要的基于氮化合物的半导体由于在激光和其他光学设备中的潜在应用而成为密切关注的焦点，这些半导体工作在光谱的蓝/紫外区。这些材料被称为宽带隙氮化物半导体，也有望用于温度比传统材料高得多的电子设备。虽然已经用这些材料制造了许多简单的器件，但对它们的基本电子和化学性质仍然严重缺乏了解。了解这些材料的基本性质对于这些材料的充分商业开发至关重要，因为例如，氮化物表面附近的电子行为控制着它们的化学反应活性、结构稳定性以及其他材料与它们结合的方式。这个单独的研究项目将使用两个探测器来研究这些材料的基本电子性质：光电子能谱和X射线发射光谱。这些探测器包括通过用强烈的x射线照射材料中的电子并测量它们的响应来为它们提供额外的能量。光谱的这种组合将提供对这些半导体的电子和化学性质的全面了解。该计划还将培养博士后研究助理、研究生和本科生半导体材料的物理和化学，以及最先进的光谱探头在他们的研究中的应用。该项目由美国国家科学基金会材料研究部和陆军研究组织物理部共同资助。

Wide band gap nitride semiconductors are the focus of intense scrutiny due to their potential applications in optoelectronic, high temperature, and spintronic devices. However, our understanding of the basic physics of these materials lags behind our ability to make electronic devices from them. This individual investigator award supports a project to investigate the electronic structure of clean and adsorbate-covered nitride semiconductors. The goals are to study the bulk and surface electronic structure of nitride semiconductor alloys in order to understand their fundamental electronic properties; to study gas adsorption on well characterized nitride surfaces in order to understand their chemical reactivity, their passivation, and the growth and stability of inorganic and organic overlayers; and finally to study the electronic structure of model magnetic semiconductors such as GaMnN. This project will have a significant impact on the education of students and postdoctoral research associates by exposing them to a highly collaborative research environment at national user facilities. They will be educated in the physics of novel semiconductor materials, and in the application of synchrotron radiation spectroscopies in their study. This is an ambitious program that aims to produce definitive measurements of surface and bulk electronic structure in wide band gap semiconductors. The project is co-funded by the Division of Materials Research at NSF and the Physics Division at the Army Research Organization.An important new class of semiconductors based on nitrogen compounds are the focus of intense scrutiny due to their potential applications in lasers and other optical devices that operate in the blue/UV portion of the spectrum. These materials, know as wide band gap nitride semiconductors, also hold the promise of being used in electronic devices operating at much higher temperatures than conventional materials. While many simple devices have been fabricated from these materials, there remains an acute lack of knowledge about their fundamental electronic and chemical properties. It is of vital importance for the full commercial exploitation of these materials to understand their basic properties since, for example, the behavior of electrons near the nitride surface controls their chemical reactivity, their structural stability, and how other materials are bonded to them. This individual investigator project will study the basic electronic properties of these materials using two probes: photoemission spectroscopy and x-ray emission spectroscopy. These probes involve providing the electrons in the material with additional energy by illuminating them with intense x-rays and measuring their response. This combination of spectroscopies will provide a comprehensive understanding of the electronic and chemical properties of these semiconductors. This program will also educate postdoctoral research associates, graduate and undergraduate students in the physics and chemistry of semiconductor materials, and the application of state of the art spectroscopic probes in their study. The project is co-funded by the Division of Materials Research at NSF and the Physics Division at the Army Research Organization.