Hybrid silver selenide colloidal quantum dot - amorphous avalanche selenium infrared detectors (Electronics Sensing) (STIR)
Abstract
To aid and maintain highest level of mobility and situational awareness, future military systems in the Army are intended to conduct day/night and degraded visual environment (DVE) missions in conditions such as haze, dense fog, smoke, turbulence and even sand and dust to enable ground vehicle maneuvering (tanks, trucks etc.), automated human detection, vehicle detection and tracking, identify targets and perform threat assessment. In addition, threat warning systems such as infrared countermeasures (IRCM) and hostile fire indication (HFI) are necessary on ground vehicles for missile and rocket mitigation and detection of small arms and rocket propelled grenade fire. All of these systems need to detect unresolved signals and operate at high speed and high frame rate, to catch short duration events with low false alarms. Current technology that involves radar, night-vision devices, and visual watches has been relatively unchanged since decades and is pretty much obsolete which provides a compelling motivation to design novel sensors and imaging architectures that are durable, affordable and can provide high performance and persistent surveillance. In this regard, infrared (IR) detectors have the powerful ability to resolve optical images in low visibility or obstructed environments. By extending the spectral response towards longer Mid-wave IR, detectors do not require an illumination source for imaging (passive imaging) and have the ability to see through airborne obscurants such as smoke, mist, and fog thus rendering them highly suited for applications that require capabilities unmet by visible and near-IR detectors. The aim is to design novel Mid-wave and Short-wave IR detectors and imagers by coupling recently discovered IR-active Ag2Se colloidal quantum dots (CQDs) with amorphous-Selenium (a-Se) avalanche photodiodes, operating at room temperature with extremely low noise and SWaP-C (size, weight, power and cost) compared to the well-established mercury cadmium telluride (HgCdTe) detectors. In particular, this project aims to use Ag2Se CQDs as a new environmentally benign and non-toxic IR photon absorber and couple those to an a-Se transport layer utilizing an avalanche phenomenon to increase the signal-to-noise ratio (SNR) generating extremely sensitive IR detectors and imagers under photon-starved conditions. This approach focuses on ameliorating the issues with typical CQD-based detectors and a-Se avalanche detectors by coupling and exploiting the best features of both technologies to deliver a highly efficient IR detector. The overarching goal of this research proposal is to fabricate a p-i-n vertical-stack photodetector, using room-temperature, solution-processed IR Ag2Se CQD photoconversion layer, with an a-Se layer acting as a wide-bandgap charge transport layer. The ultimate aim is to demonstrate devices based on this hybrid a-Se:CQD system that would demonstrate high detectivity in the SWIR and the MWIR spectral regions, operating at high temperature (> 200K) accessible through a solid-state Peltier cooling device. The success of this project will have a huge impact on the IR imaging and sensing area which is currently dominated by the toxic HgCdTe detectors operating at cryogenic temperatures and enable a low-cost, high performance IR imaging technology that will be ubiquitously utilized in a broad range of defense applications. Also, the results will provide a road map for integrating CQDs in mainstream commercial IR applications and not just restrict to military and astronomy applications. Additionally, through this proposed work, fundamental and practical understanding of Mid-IR detector technology will be advanced by focusing on the structure-property relationship of IR-active CQDs.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 25, 2021
- Source ID
- W911NF2110056
Entities
People
- Ayaskanta Sahu
Organizations
- Army Contracting Command
- New York University
- United States Army