Carrier recombination dynamics in III-N photodetectors

III-N 光电探测器中的载流子复合动力学

• 批准号: 2341747
• 负责人: Leonid Chernyak
• 金额: $ 38.72万
• 依托单位: The University of Central Florida Board of Trustees
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-05-01 至 2027-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2341747&HistoricalAwards=false
• 关键词: Carrier; recombination; dynamics; III; photodetectors

Ultraviolet photodetectors have many uses, such as chemical and biological analysis or flame detection. Damage by energetic particles degrades the sensitivity of ultraviolet photodetectors in harsh radiation environments. This project will study techniques for recovery of photodetectors based on gallium nitride (GaN). This aim will be achieved by electrical tailoring of GaN fundamental properties, the electron lifetime and diffusion length, by in-situ charge injection under applied voltage. Photodetector sensitivity will recover completely and return to the original state prior to irradiation. The project will advance the fundamental understanding of the nature of point and extended defects in GaN-based semiconductors and devices. The project will integrate research and education at the graduate and undergraduate levels and features an active industrial partner.Technical: This project focuses on electrical mitigation of radiation-induced defects by charge injection into ultraviolet photodetectors based on gallium nitride (GaN). The ultimate aim is to produce radiation hard and efficient devices. The project hinges on the PI's previous findings that charge injection into p-type GaN leads to considerable changes in the material's fundamental electronic properties, particularly the carrier lifetime and diffusion length. These changes result in an order of magnitude enhancement of the photodetector response (quantum efficiency). It is therefore possible to improve performance of photodetectors, affected by radiation, using short pulses of solid-state forward-bias charge injection into GaN p-i-n devices. The project will lead to a better understanding of the interaction between wide band gap semiconductors and highly energetic particles, including electrons, gamma-ray photons and protons, as well as of the nature of radiation-induced defects. Charge injection will result in enhanced minority electron diffusion length in the top p-type absorption layer of a photodetector, thus increasing the quantum efficiency for the device and "healing" the adverse impact of highly energetic particles. A unique combination of electrical and optical studies in the PI’s lab will shed light on the mechanism, which is responsible for the effect of interest. Studies of minority carrier lifetime and diffusion length will be carried out in independent experiments using ultrafast time-resolved cathodoluminescence and electron beam-induced current at various temperatures. Polychromatic continuous-wave cathodoluminescence will be employed for assessment of irradiation impact on threading dislocation density in GaN. Finally, the ultimate goal of this project is to correlate charge injection regimes (current; voltage; duration) and irradiation doses, thus proceeding towards control of photodetector performance and recovery from radiation damage by purely electrical means.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

紫外光电探测器有许多用途，如化学和生物分析或火焰探测。高能粒子的损伤会降低紫外线探测器在恶劣辐射环境中的灵敏度。本项目将研究基于氮化镓（GaN）光电探测器的回收技术。这一目标将通过施加电压下的原位电荷注入来实现氮化镓的基本性质、电子寿命和扩散长度的电剪裁。光电探测器的灵敏度将完全恢复到辐照前的原始状态。该项目将促进对gan基半导体和器件中点缺陷和扩展缺陷本质的基本理解。该项目将整合研究生和本科生的研究和教育，并拥有一个积极的工业合作伙伴。技术：该项目侧重于通过向基于氮化镓（GaN）的紫外光电探测器注入电荷来减轻辐射引起的缺陷。最终的目标是生产出辐射坚硬而高效的设备。该项目依赖于PI之前的发现，即向p型GaN注入电荷会导致材料基本电子特性发生相当大的变化，特别是载流子寿命和扩散长度。这些变化导致光电探测器响应（量子效率）的一个数量级增强。因此，利用短脉冲固态正偏电荷注入GaN p-i-n器件，可以改善受辐射影响的光电探测器的性能。该项目将使人们更好地理解宽带隙半导体与高能粒子（包括电子、伽马射线光子和质子）之间的相互作用，以及辐射诱发缺陷的本质。电荷注入将导致光电探测器顶部p型吸收层中少数电子扩散长度的增加，从而提高器件的量子效率并“治愈”高能粒子的不利影响。PI实验室的电学和光学研究的独特结合将揭示产生兴趣效应的机制。利用超快时间分辨阴极发光和电子束感应电流在不同温度下进行独立实验，研究少数载流子寿命和扩散长度。采用多色连续波阴极发光技术评价辐照对氮化镓中螺纹位错密度的影响。最后，该项目的最终目标是将电荷注入制度（电流、电压、持续时间）与辐照剂量联系起来，从而朝着控制光电探测器性能和通过纯电手段从辐射损伤中恢复的方向发展。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。