Tunable Optoelectronic Materials for Next-Generation Infrared Detectors

Project Overview

State-of-the-art infrared (IR) photodetectors are used across a multitude of fields, including defense, astronomy, and medicine, for chemical and thermal imaging and tracking. However, these IR photodetectors require expensive sensing materials (i.e., single crystalline HgCdTe or InSb wafers grown by molecular beam epitaxy) and require cooling to achieve their state-of-the-art performance, increasing the system's cost and physical footprint. Quantum dots (QDs), which are soluble semiconductor particles with nanoscale dimensions having altered optical and electronic properties, have been proposed as a potential sensing material for next-generation IR cameras. The benefits of QD-based IR cameras include that they could be produced for far less cost and could potentially achieve high performance at higher operating temperatures--all of which would enable use of IR cameras in more settings and applications.

Recent research into QD-based IR photodetectors has primarily focused on toxic lead- and mercury-based materials and the performance of these QD devices is still behind current commercial IR cameras that use single crystalline materials. In our work, we investigated a non-toxic alternative quantum dot--silver selenide--and investigated chemistry and processing strategies to increase the performance of silver selenide QD-based photodetectors. With our developed strategies, we produced single-pixel photodetector devices that have the highest performance reported to-date for QD-based devices (as measured by responsivity), and this performance was achieved at room temperature without any cooling. Extending these results to multipixel devices, the realization of low-cost, high-performance IR cameras capable of operating at relatively high temperatures may indeed be within grasp.

Mission Impact

Completing the objectives of our project required bringing several new capabilities to the lab, including an optoelectronic device testing station, a heated slot-die coater, and an IR integrating sphere. All these capabilities have strengthened Lawrence Livermore National Laboratory's ability to develop science and technology tools and capabilities to meet future national security challenges. This work resulted in the hiring of a new postdoc with expertise in quantum dot synthesis and expanding his skillset to include study of materials in the infrared regime and development of quantum-dot based photodetectors. This work also enabled us to explore solutions to emerging security challenges associated with technology surprise in the space and military domains.

Publications, Presentations, and Patents

A.M. Hiszpanski. "Scalable Fabrication of the Nanoscale for Metamaterials and Photodetectors." Invited presentation at IPRIME Workshop. University of Minnesota. Minneapolis, MN. May 29^th, 2019.

Tom Nakotte, Jinkyu Han, Anna M. Hiszpanski. "Surface Treatment Methods to Improve Colloidal Stability of In-Solution Ligand Exchanged Ag2Se Quantum Dots."2021, ROI: IL-1366201.

Tom Nakotte, Jinkyu Han, Anna M. Hiszpanski. "Surface Treatment for Colloidal Stability of In-Solution Ligand Exchanged Quantum Dots." 2021, Patent Application Submitted.