Setting LWIR state of the Art using T2SL detectors (LIRA)

红外区域已经成为光子学未来的下一个前沿，它提供了我们肉眼看不到的环境中的关键信息。需要高性能探测器，即具有高探测率（低暗电流和高量子效率）的量子（光子）红外探测器，用于特定的军事（士兵视觉增强、导弹跟踪/导引头）和空间（地球观测）应用。该博士研究项目将专注于II型超晶格（T2 SL）材料作为器件吸收区域，因为它被认为是下一代高性能红外成像系统（高工作温度，多光谱，大型焦平面阵列）的有希望的候选者。由于其独特的性能，这种材料在理论上有可能在长波红外（LWIR）光谱域中超越最先进的红外技术，如碲镉汞（MCT）和GaAs/GaAlAs量子阱红外光电探测器。然而，其理论性能尚未达到;这与T2 SL材料中的缺陷导致的低少数载流子寿命直接相关。我们实现高性能探测器的方法是探索T2 SL设计、外延和整体器件设计之间的关系，以在8- 12微米光谱范围内实现最先进的性能。我们将探讨在这一波长范围内最重要的挑战，并开发那些有前途的方法对室温操作的长波红外探测器和焦平面阵列。我们将确定在分子束外延生长的外延层的缺陷类型，然后减轻其对器件性能的影响。我们将探索复杂的设备设计和架构。此外，我们将比较天然的GaSb衬底，工业相关的GaAs和确定的最佳组合的衬底（材料，类型，方向）和工业应用，放大和潜在的焦平面阵列发展的设备设计。

The infrared regime has become the next frontier in the future of photonics providing crucial information from our environment which we cannot see with our eyes. There is a need for high-performance detectors, i.e. quantum (photonic) infrared detectors with high detectivity (low dark current and high quantum efficiency), for specific military (soldier vision enhancement, missile tracking/seeker) and space (earth observation) applications. This PhD research project will focus on Type-II SuperLattice (T2SL) material as the device absorption region since it is considered a promising candidate for the next generation of high-performance infrared imaging systems (high operating temperature, multispectral, large focal plane array). Thanks to its unique properties, this material has theoretical potential to outperform, in the long-wavelength infrared (LWIR) spectral domain, state-of-the-art infrared technologies such as Mercury Cadmium Telluride (MCT) and GaAs/GaAlAs Quantum Well Infrared Photodetector. However, its theoretical performance has not yet been reached; this is directly related to the low minority carrier lifetime due to defects in the T2SL material. Our approach to achieve high-performance detectors is to explore the relationship between T2SL design, epitaxy and overall device design to achieve state-of-art performance in the 8-12micrometre spectral regime.This project has great opportunity for scientific and industrial impact. We will explore the most important challenges in this wavelength regime and develop those promising approaches towards room-temperature operation of LWIR detectors and focal-plane arrays. We will identify defect types in the MBE-grown epilayers then mitigate their influence on device performance. We will explore sophisticated device design and architecture. Moreover, we will compare native GaSb substrates to industrially relevant GaAs and identify the optimum combination of substrate (material, type, orientation) and device design for industrial application, scale-up and potential focal plane array development.