非极性面氮化物子带间跃迁结构外延生长及红外探测器研究

III-nitride quantum well infrared photodetector based on intersubband transition (ISBT) has recently attracted extensive attention for the applications of infrared remote sensing, night vision, thermal imaging, missile guidance/warning, and so on. However, the device suffers from lattice polarization for III-nitride grown along c-axis, largely reducing the vertical photocurrent transport. Thus it’s of vital importance to develop a method solving the polarization-induced internal electric field. This project, aiming at non-polar GaN-based infrared photodetector at mid-infrared spectral range, will design and fabricate samples grown on non-polar self-standing GaN substrates. Crack-free AlGaN multiple quantum well (MQW) structure can be obtained through stress engineering by precise controlling in MBE. The method of heavy n-type doping is also studied, then infrared photo-absorption response can be measured through high-quality non-polar MQW. The research on fabrication of mesa structure for small size samples is needed for the electrical measurements. After the reducing of dark current density in the device, prototype device of non-polar III-nitride ISBT infrared photodetector can be achieved.

基于氮化物子带间跃迁的量子阱红外探测器是近年来国际上备受关注的热点研究领域，在远距离遥感、夜视、热成像、导弹制导等应用领域具有重要的意义。然而，通常的c面氮化物材料存在强极化电场严重限制了载流子纵向输运进而影响红外探测效率，寻找一种根本上解决极化场的技术方案对氮化物子带间跃迁红外探测至关重要。本申请项目以实现中红外波段非极性面氮化物红外探测器为目标，采用MBE方法在非极性面自支撑GaN衬底上通过应力调控生长技术抑制外延层表面开裂，同时优化高效n型掺杂方法，生长高质量非极性面多量子阱结构，实现中红外光吸收探测；研究小尺寸样品的台面工艺流程，通过器件测试反馈研究影响暗电流的因素，优化抑制暗电流方案，最终实现非极性面氮化物子带间跃迁红外探测器原型器件。

氮化物量子阱子带间跃迁结构在红外探测及多色探测集成方面具有优势，在红外成像、制导、预警等领域有应用价值。本项目研究了GaN基量子阱子带间跃迁红外探测，通过MBE方法制备了一组非极性面GaN多量子阱结构，并对该结构进行侧面抛光及台面工艺、电极蒸镀的器件制备，通过自主搭建的低温FTIR系统对器件进行了红外光吸收和红外光电流探测，实现了3-5μm中红外波段光吸收的调制，以及中心波长~4μm波段红外光电流的探测。此外，本项目还通过GaN多量子阱结构展示了紫外-红外双色探测，紫外波段截止边在350nm，红外波段吸收峰在1.5μm光通讯波段。针对c面GaN量子阱子带间跃迁结构中面临的极化场问题设计了准平带结构，并以此结构实现了中心波长2.5-4μm中红外波段光吸收的调制。以上研究为高质量非极性面氮化物材料及其红外探测器件研制提供了新思路。.