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

非技术描述：该项目研究含有两种或两种以上金属氮化物的新型复合材料的基本材料问题。这些材料之所以令人感兴趣，是因为它们在新型光电子器件中的潜在用途，这些光电子器件对社会有益的技术应用(传感、成像和电信)具有重要意义。由于它们的物理和化学性质非常不同，当这些复杂的化合物一起生长在一起时，形成了各种独特的纳米结构，这些厚厚的堆栈有很多层。这个项目的目的是在纳米尺度上了解、控制和定制材料的局部原子排列，以最大限度地增加在不可见红外范围内的光吸收。该项目还探索了纳米结构对自由电荷局部转移的影响。特别感兴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内部或在当地学校组织的外联活动，以增加K-12学生和普通公众对物理学、材料科学和工程学之间的现代科学主题的接触。技术描述：本项目的主要目标是建立用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学(发射器和探测器)中的应用至关重要。研究工作包括AlIn(Ga)N/(In)GaN异质结的材料设计和生长，以及结构和光学材料的表征。氮化物异质结构的生长促进了氮化物外延技术的发展。为了将纳米结构与光学性能联系起来，用高分辨X射线衍射仪和透射电子显微镜对半导体材料的原子结构进行了详细的表征，并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，使导带工程能够用于光发射。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。参与这个项目的学生有机会获得最新的纳米材料、制造和表征工具和技术的经验。拟议外联计划的一个特别重点是加强任职人数不足的群体，特别是女性对物理科学和工程学的参与。

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.