Identification of point defects in GaN materials and their impact on device performance

GaN 材料中点缺陷的识别及其对器件性能的影响

• 批准号: 2734689
• 金额: --
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2734689
• 关键词: Identification; point; defects; GaN; materials

The project proposes to extend the electrical characterisation techniques used for smaller gap materials by the Manchester group for decades to measure the electrical properties of defects in wide band gap semiconductors. The most important wide gap materials at the present time are GaN and InGaN. They are used to make low energy LED lighting and highpower transistors. Today's generation of these devices does not function as well as would seem possible from the properties of the materials and at the present time functionality and performance is limited. This is due, at least in part, to the presence of point defects in the component materials and devices. Eg, In LEDs so called Shockley-Reed-Hall recombination due to gap states is still a significant efficiency loss mechanism. The student will use deep level transient spectroscopy and photoluminescence techniques to identify the nature of the point defects in these materials and how they impact on real LED and transistor devices. Particular defects and impurities will be introduced, either by the industrial collaborator during growth or by using eg implantation or irradiation. The resulting defect energy levels will be then characterised using the techniques described, and the impact of device performance assessed. The nitride materials are still their infancy as semiconductors, they contain high levels of point defects, vacancies, interstitials and impurities such as carbon. The electronic behaviour of these defects is almost completely unknown. What is known is that real world devices show undesirable properties such as current collapse in transistors and anomalous efficiency droop in LEDs. These effects are believed to be due to defect states, but as of today there is no definitive demonstration of what defect is responsible. This project represents a tremendous opportunity to perform world class, high impact, research in this area.

该项目提议将曼彻斯特小组用于较小间隙材料的电学表征技术扩展数十年，以测量宽带隙半导体中缺陷的电学特性。目前最重要的宽禁带材料是GaN和InGaN。它们用于制造低能耗 LED 照明和高功率晶体管。当今一代的这些设备的功能并不像材料特性所想象的那样好，并且目前功能和性能受到限制。这至少部分是由于元件材料和器件中存在点缺陷。例如，在 LED 中，由于间隙态而导致的所谓 Shockley-Reed-Hall 复合仍然是一种显着的效率损失机制。学生将使用深层次瞬态光谱和光致发光技术来识别这些材料中点缺陷的性质以及它们对实际 LED 和晶体管器件的影响。特定的缺陷和杂质将由工业合作者在生长过程中或通过使用例如注入或辐射引入。然后将使用所描述的技术来表征所产生的缺陷能级，并评估器件性能的影响。氮化物材料作为半导体仍处于起步阶段，它们含有大量的点缺陷、空位、填隙和碳等杂质。这些缺陷的电子行为几乎完全未知。众所周知，现实世界的设备表现出不良特性，例如晶体管的电流崩溃和 LED 的异常效率下降。这些影响被认为是由缺陷状态造成的，但截至目前，还没有明确的证据表明是什么缺陷造成的。该项目为在该领域进行世界级、高影响力的研究提供了巨大的机会。