A Thermal-Electrically Cooled Quantum-Dot Multi-spectral Photodetector and Focal Plane Array with High Photodetectivity

Highly-sensitive multi-spectral photodetectors and imaging arrays are of great importance in numerous applications, including thermal remote sensing, environment monitoring, missile tracking and discrimination, material analysis and medical diagnostics. There are generally two types of imaging sensors, i.e. (1) thermal detectors and (2) photodetectors. Thermal detectors are slow in response and have limited sensitivity, making them unsuitable for fast and highly sensitive infrared imaging. Photodetectors are intrinsically fast and have high sensitivity. However, existing middle wave infrared (MWIR) and longwave infrared (LWIR) photodetectors are required to be cooled down to a low temperature of 77K to reduce dark current. The requirement for cryogenic cooling systems adds cost, weight and reliability issues. The proposed research aims to develop capable of thermal-electrically (TE) cooled multi-spectral (LWIR, MWIR and LWIR) quantum dot infrared photodetector (QDIPs) with fast response and high sensitivity. Such TE-cooled multi-spectral IR photodetector avoids the difficulty associated with cryogenic cooling systems and provides a reliable IR imaging technology for small and micro unmanned air vehicles (UAVs) and standalone applications. In phase I, a preliminary TE-cooled multi-band QDIP will be developed for proof-of-concept demonstration. In Phase II, a prototype of ultra-compact TE-cooled 1Kx1K focal plane array (FPA) will be developed and delivered to Air force research lab. BENEFIT: The proposed innovation provides an enabling technology for thermal-electrically (TE) cooled multi-spectral imaging FPAs with high sensitivity. This kind of ultra-sensitive thermal-electrically FPAs not only significantly enhances detecting sensitivity and spatial and temporal resolution, but also substantially reduces costs, size, weight and power consumption and improve the system reliability. It forms a key building block for highly reliable and standalone IR imaging systems for high-speed target detection, identification and discrimination systems. Commercial markets include portable IR sensing and imaging systems for atmospheric pollution and drug monitoring, spectroscopy, and medical diagnoses. The technology developed herein is expected to significantly advance IR imaging technologies and greatly accelerate the commercialization of the ultra-compact and portable multi-spectral IR imaging technologies to meet the potential needs of the billion-dollar defense and commercial market.