Collaborative Research: Fundamental Studies of the Properties of B-III-N Wide-Bandgap Semiconductor Alloys

非技术描述：该合作研究项目研究了一种尚未开发的半导体材料系统，该系统涉及硼掺入BAlGaN的四元素合金中。这些材料是新一代III-V合金系统，与已经开发的AlInGaN合金相比，提供高效照明。以AlInGaN合金为基础的固态照明和照明技术，在汽车、液晶显示背板、移动通信和标牌照明等领域已经有了广泛的实际应用，并将很快在普通照明领域占据主导地位。然而，AlInGaN合金材料仍然存在重要的局限性。本研究项目旨在探索在这些合金中加入硼的优势，最终目标是在异质结构中实现更好的应变匹配、更高的效率和潜在的p型掺杂。该研究与教育活动相结合，包括对研究生和本科生的研究培训，包括这些新材料的生长、表征和加工，以及乔治亚理工学院和亚利桑那州立大学的各种推广项目。技术描述：本研究项目的主要重点是研究高质量含硼iii -氮化半导体三元和四元合金薄膜的物理、化学和电子特性，这些薄膜在技术上具有重要的组成范围，并深入了解基础材料科学，以改进光电器件设计。研究团队采用先进的金属有机化学气相沉积（MOCVD）外延膜生长系统，对生长条件、衬底材料、衬底取向和掺杂的影响进行了深入的研究。使用最先进的纳米级表征工具详细研究了材料的特性：使用原子分辨率像差校正透射电子显微镜研究了晶体结构；电子能带结构由电子全息测定；利用高时空分辨率的阴极发光技术对其光学性能进行了测量。研究还包括了成分均匀性、相分离和压电场的影响。显微结构性能与光电性能相关联，以了解生长参数对整体器件性能的作用。

Non-technical Description: This collaborative research project studies an underexplored semiconductor materials system that involves boron incorporation in the four-element alloys of BAlGaN. These materials are a new generation of III-V alloy system compared to the AlInGaN alloys that have been developed to provide high-efficiency lighting. The solid-state illumination and lighting technology, based upon AlInGaN alloys, has found wide practical applications in automotive, liquid-crystal-display back panel, mobile communications and signage illumination, and will soon dominate in general lighting. However, there are still important limitations for AlInGaN alloy materials. This research project explores the advantages of incorporation of boron into these alloys with the ultimate goal to achieve better strain matching in heterostructures, higher efficiency and potentially p-type doping in the new alloy system. The research is integrated with the educational activities including research training for graduate and undergraduate students in the growth, characterization, and processing of these novel materials, and various outreach programs at both Georgia Institute of Technology and Arizona State University.Technical Description: The primary focus of this research project is to study the physical, chemical, and electronic properties of high-quality thin films of boron-containing III-nitride semiconductor ternary and quaternary alloys in the technologically important range of compositions and to develop an in-depth understanding of fundamental materials science for improved optoelectronic device designs. The research team uses advanced metalorganic chemical vapor deposition (MOCVD) epitaxial film growth systems, and performs in-depth studies of the effects of growth conditions, substrate materials, substrate orientation, and doping. The materials properties are studied in detail using state-of-the-art nanoscale characterization tools: the crystal structure is studied using atomic-resolution aberration-corrected transmission electron microscopy; the electronic band structure is determined by electron holography; and the optical properties are measured by cathodoluminescence with high spatial- and temporal-resolution. Exploring the effects of compositional homogeneity, phase separation, and piezoelectric fields is also included in the research. The microstructural properties are correlated with the optoelectronic properties to understand the role of growth parameters on overall device performance.