CAREER: Engineering point defect formation in UWBG-based optoelectronic devices

职业：基于 UWBG 的光电器件中工程点缺陷的形成

• 批准号: 1653383
• 负责人: Ramon Collazo
• 金额: $ 50万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-03-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1653383&HistoricalAwards=false
• 关键词: CAREER; Engineering; point; defect; formation; CAREER; Engineering; point; defect; formation

Many applications such as optoelectronics and power electronics rely on the functionality of ultra wide bandgap materials. But to reach their full potential, it is necessary to understand and realize novel processes to enhance their performance, either electrically or optically. The proposed processing framework has the opportunity of revolutionizing these family of materials, thus providing for the achievement of properties that otherwise will not be attainable. This is in addition to providing a unifying conceptual approach consistent with modern computational efforts that bring about a non-Edisonian approach to the design of materials and processes dealing with this class of materials. This research will directly lead to applications that deal with the preservation and extension of natural resources by allowing for: the availability of clean potable water through disinfection by the use of ultraviolet light emitting diodes, and the detection of pollutants and other effluents. The novel concepts developed within this project can also be implemented in the educational and outreach efforts (some specifically targeted at minority students), especially integrating materials characterization and control schemes to applications dealing with the need for the development of materials for sustainability purposes. This program will provide the opportunity to educate Ph.D. students on the growth, characterization and device fabrication of these materials while participating on an established international collaborators network. Furthermore, integration of these ideas into design of new courses broadens the community of students and experts related to the topic, especially those dealing with computational methods. From this, graduate students and group members will be able to effectively discuss their research for fruitful collaborations while accelerating their professional growth.Charged point defects in compound semiconductors strongly determine electronic and optical properties. The energy of formation of a point defect is a function of the process conditions and the Fermi energy. In ultra wide bandgap materials or insulators, the contribution of the Fermi energy to the formation energy of charged point defects is significant. For the practical case of doping for n- or p-type conductivity, the larger the energy gap, the higher the concentration of compensating point defects that is at equilibrium with the system. This is a fundamental problem of these materials that will be directly addressed with these capabilities. In this approach, we will extend the concept of the quasi-Fermi level in an effort to quantify the impact of external excitation in the formation energy of the point defect. Increasing the formation energy of unwanted point defect through external excitation during a growth experiment leads to a reduction in compensating point defects and higher device efficiencies. The research objective of this proposal is to test the hypothesis that the energy of formation of charged point defects could be manipulated by an external excitation in a steady-state condition during growth. Approaches include the introduction of above-bandgap illumination or e-beam irradiation as excitation sources. This process is referred to as Fermi level control of point defects. Three main research tasks are designed to test the hypothesis: (1) demonstration of Fermi level control of technologically important point defects during the growth of III-nitrides based UV LED structures, (2) optical and electrical study of point defects and their influence on the device performance, (3) extension to other wide bandgap systems and alternative Fermi level management processes to show universality of the process. This research will extend these capabilities to AlGaN for the engineered reduction of compensating and non-radiative defects in deep UV LEDs. It is expected that this process is generally applicable to a broad class of wide bandgap materials, in particular, several oxide systems.

许多应用，例如光电和电力电子设备，都依赖于超宽带镜头材料的功能。但是，为了发挥其全部潜力，有必要理解并实现新颖的过程以在电或光学上提高其性能。拟议的处理框架有机会彻底改变这些材料家族，从而实现否则将无法实现的财产。这是为了提供与现代计算工作相一致的统一概念方法的补充，该方法为设计与此类材料的材料和过程设计了一种非埃迪生人的方法。这项研究将直接通过允许：通过使用紫外线发光二极管通过消毒而供自然资源的保存和扩展的应用，并发现污染物和其他废水。该项目中开发的新颖概念也可以在教育和推广工作中实施（一些针对少数族裔学生），尤其是将材料表征和控制方案整合到应对可持续性目的开发材料的应用中的应用中。该计划将提供教育博士学位的机会。在参与建立的国际合作者网络时，这些材料的增长，表征和设备制造的学生。此外，将这些思想集成到新课程的设计中，扩大了与该主题相关的学生和专家社区，尤其是那些处理计算方法的人的社区。由此，研究生和小组成员将能够有效地讨论他们的研究研究，同时加速其专业成长。复合半导体中的充电点缺陷强烈确定了电子和光学特性。点缺陷的形成能量是过程条件和费米能量的函数。在超宽的带隙材料或绝缘子中，费米能量对带电点缺陷的形成能的贡献是显着的。对于掺杂N-或P型电导率的实际情况，能量隙越大，与系统平衡的补偿点缺陷浓度越高。这是这些材料的基本问题，这些材料将直接解决这些功能。在这种方法中，我们将扩展准Fermi级别的概念，以量化外部激发在点缺陷的形成能量中的影响。在增长实验过程中通过外部激发增加不需要点缺陷的形成能，导致补偿点缺陷和较高的设备效率的降低。该提案的研究目的是检验以下假设：在生长过程中，在稳态状态下，外部激发可以通过外部激发来操纵带电点缺陷的能量。方法包括引入带有带有式照明或电子束照射作为激发源。该过程称为点缺陷的费米级控制。旨在测试假设的三个主要研究任务：（1）在基于III-氮化物的紫外线LED结构的增长过程中，FERMI级别控制了技术重要的点缺陷，（（2）点缺陷的光学和电气研究及其对设备性能的影响，（3）扩展到其他广泛的Bandgap Systems和其他范围的Fermi级别管理流程，以展示流程，以展示流程，以展示流程。这项研究将把这些能力扩展到Algan，以设计深紫外线中的补偿和非辐射性缺陷。预计该过程通常适用于广泛的宽带镜头材料，特别是几种氧化物系统。