Novel Infrared Optical Materials Based on III-Nitride Semiconductors: Growth, Structure and Properties

非技术描述：本项目研究一类含有两种或多种金属氮化物的新型复杂材料的基本材料问题。这些材料很有趣，因为它们在新型光电器件中的潜在用途对社会有益的技术应用（传感、成像和电信）很重要。由于它们的物理和化学性质非常不同，这些复杂的化合物在一起生长时形成各种独特的纳米结构。该项目旨在了解、控制和定制纳米级材料的局部原子排列，以最大限度地吸收不可见的红外范围内的光。该项目还探讨了纳米结构对自由电荷局部转移的影响。特别有趣的是晶体取向对光学和电学性质的影响。参与该项目的主要研究人员、学生和高中教师参加了在学校内部或当地学校组织的推广活动，以增加K-12学生和公众对物理、材料科学和工程之间的现代科学主题的接触。技术描述：本项目主要目的是建立等离子体辅助分子束外延在c-和m-平面GaN上生长的AlIn(Ga)N/(In)GaN多量子阱结构的生长、原子结构和红外光学性质之间的关系。该项目特别侧重于揭示纳米结构对红外子带间吸收的影响，这一特性对于这些材料在新型红外光电子（发射器和探测器）中的应用至关重要。研究工作包括材料设计和生长，以及AlIn(Ga)N/(In)GaN异质结构的结构和光学材料表征。氮化物异质结构的生长促进了氮化物外延的发展。为了将纳米结构与光学性质联系起来，利用高分辨率x射线衍射和透射电子显微镜对半导体材料的原子结构进行了详细表征，同时利用傅里叶变换红外光谱对材料的红外光学性质进行了实验研究。第二个目标是开发预测材料建模能力，使光发射的导带工程成为可能。该研究项目还通过将跨学科研究与更广泛的物理和工程教育和培训相结合，增加了学生在传统课堂内外的学习机会。参与该项目的学生有机会获得最新纳米材料制造和表征工具和技术的经验。拟议的外联计划的一个特别重点是加强代表性不足的群体，特别是妇女对物理科学和工程的参与。

Nontechnical Description: This project investigates fundamental materials issues of a new class of complex materials containing two or more metal nitrides. These materials are interesting because of their potential use in novel optoelectronic devices of importance for technological applications beneficial to society (sensing, imaging, and telecommunications). Due to their widely dissimilar physical and chemical properties, these complex compounds form a variety of unique nanostructures when grown together in thick stacks of many layers. This project aims to understand, control, and tailor the local atomic arrangement of the materials at the nanoscale to maximize light absorption in the invisible infrared range. The project also explores the effect of nanostructure on local transfer of free electrical charge. Of particular interest is the impact of the crystal orientation on optical and electrical properties. The principal investigators, students and high-school teachers involved in this project participate in outreach activities organized either in-house or at local schools to increase exposure of K-12 students and the general public to modern scientific topics at the border between physics, material science, and engineering. Technical Description: The main objective of this project is to establish the relationship between growth, atomic structure and infrared optical properties of AlIn(Ga)N/(In)GaN multi-quantum well structures grown by plasma-assisted molecular beam epitaxy on c- and m-plane GaN. The project particularly focuses on unraveling the impact of nanostructure on infrared intersubband absorption, a property that is essential for the application of these materials in novel infrared optoelectronics (emitters and detectors). The research effort involves material design and growth, as well as structural and optical material characterization of AlIn(Ga)N/(In)GaN heterostructures. The growth of nitride heterostructures advances the state-of-the-art in nitride epitaxy. In order to correlate the nanostructure with optical properties, the atomic structure of the semiconductor materials is characterized in detail using high-resolution x-ray diffraction and transmission electron microscopy, while the infrared optical properties of the materials are examined experimentally using Fourier transform infrared spectroscopy. A secondary goal is developing of predictive material modeling capabilities that enable conduction-band engineering for light emission. The research project also increases the learning opportunities for students, inside and outside the traditional classroom by integrating interdisciplinary research with broader physics and engineering education and training. The students involved in this project have the opportunity to acquire experience with the latest nanomaterials fabrication and characterization tools and techniques. A special thrust of the proposed outreach plan is enhancement the participation of underrepresented groups, in particular of females, in physical sciences and engineering.