Exploiting Novel Device Structures for Deep Ultraviolet Emitters

利用深紫外发射器的新型器件结构

• 批准号: 1402886
• 负责人: Jingyu Lin
• 金额: $ 32.49万
• 依托单位: Texas Tech University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1402886&HistoricalAwards=false
• 关键词: Exploiting; Novel; Device; Structures; Deep

Abstract Title: Exploiting Novel Device Structures for Deep Ultraviolet Emitters Development of chip-scale deep ultraviolet (DUV) light sources is required for a wide range of applications such as probing intrinsic fluorescence in a protein, medical equipment/personnel decontamination, and photocatalysis. The external quantum efficiency (EQE) of Light Emitting Diodes (LEDs) operating in the region around 250 nm is still quite low (below 3%). Currently, AlGaN semiconductors are default choice for the DUV light sources. The poor p-type conductivity of Al-rich AlGaN alloys is the major obstacle that limits the EQE of these devices. Significant advances in the EQE of DUV emitters will require the exploitation of disruptive device concepts. This project aims to explore DUV device structures that exploiting new p-type layer strategies to overcome the intrinsic problem of low p-type conductivity in Al-rich AlGaN. The proposed efforts would not only yield breakthroughs in methods for the fabrication of DUV light emitting diodes (LEDs) with improved EQE, but would also lead to technological advancements in novel photonic materials and devices for a range of applications. Through the involvement in the research, students will be trained in the areas of nano-fabrication techniques, material/device design and processing using the state-of-the-art experimental facilities. The project will provide junior researchers with opportunities to participate in conferences and workshops, and gain exposure to the real world applications of DUV photonic devices. Educational activities will also include the integration of undergraduates into research via senior design projects and required project lab courses. Outreach activities include having the PIs serve as mentors of the prestigious Clark Scholars to bring an appreciation of science and technology to highly gifted high school students from around the nation and to increase diversity in science and engineering. The proposed DUV emitter layer structure is based on hexagonal boron-nitride (hBN) and AlGaN heterostructure bandgap and doping engineering. By implementing the direct wide bandgap and highly conductive hBN p-type layer strategy in nitride DUV emitters, p-type conductivities and DUV transparency of the electron blocking layer and p-type contact layer will be dramatically increased. This will significantly improve the free hole injection and EQE, reduce the operating voltage and heat generation, and increase the device operating lifetime. Control over the p-type electrical resistivity and conductivity type of epitaxial h-BN films will be established by in-situ doping via MOCVD growth. DUV emitter structures incorporating p-type hBN will be grown on sapphire with thick AlN templates to reduce the dislocation density. Ohmic contacts processing including annealing conditions will be optimized. DUV LEDs will be fabricated and their I-V, L-I characteristics, and wall plug efficiency will be correlated with the device structures and fabrication processes.

摘要标题：用于深紫外发射器的新型设备结构的开发芯片尺度深紫外线（DUV）光源是需要广泛应用的，例如在蛋白质，医疗设备/人员净化和光催化中探测内在荧光。在250 nm约250 nm的区域运行的光发射二极管（LED）的外部量子效率（EQE）仍然很低（低于3％）。目前，Algan半导体是DUV光源的默认选择。富含Al的Algan合金的P型电导率不足是限制这些设备EQE的主要障碍。 DUV发射器的EQE的重大进展将需要剥削破坏性设备概念。该项目旨在探索DUV设备结构，以利用新的P型层策略来克服富含Al的Algan中低P型电导率的内在问题。提出的努力不仅会在制造具有改进的EQE的DUV光发射二极管（LED）的方法中取得突破，而且还将导致新的光子材料和设备的技术进步，以实现一系列应用。通过参与研究，将使用最先进的实验设施对纳米制作技术，材料/设备设计和处理的领域进行培训。该项目将为初级研究人员提供参加会议和研讨会的机会，并获得DUV光子设备的现实世界应用。教育活动还将包括将大学生通过高级设计项目和所需的项目实验室课程融入研究。 外展活动包括让PI作为享有声望的克拉克学者的导师，以向来自全国的高度有天赋的高中学生带来对科学和技术的欣赏，并增加科学和工程学的多样性。拟议的DUV发射极层结构基于六角形硼氮化物（HBN）和Algan异质结构带隙和掺杂工程。通过在氮化物DUV发射器中实施直接的宽带隙和高电导性HBN P型层策略，P型电导率以及电子阻滞层的DUV透明度和P型接触层将大大增加。这将显着改善自由孔注入和EQE，降低工作电压和热量产生，并增加设备的工作寿命。 通过MOCVD生长，将建立对外延H-BN膜的P型电阻率和电导率类型的控制。融合了P型HBN的DUV发射极结构将在蓝宝石上生长，并使用厚的ALN模板生长，以降低脱位密度。包括退火条件在内的欧姆触点处理将被优化。 DUV LED将被制造，其I-V，L-I特性和壁塞效率将与设备结构和制造过程相关。