Computationally guided design of T2SL MWIR photodetectors with higher operating temperatures and larger bandwidths
Abstract
The nearly lattice-matched antimonide material system (i.e., GaSb, AlSb, InAs and their related compounds) represents the most credible alternative to mercury cadmium telluride (HgCdTe) in the infrared imaging technology. Antimonide-based type-II superlattice (T2SL) detectors hold the promise for the development of high-performance and low-cost mid-wavelength infrared (MWIR) photodetectors for navigation in low-visibility environments, weather surveillance, and search and rescue operations. III#V semiconductors are more robust than their II#VI counterparts due to stronger, less ionic chemical bonding. Besides the high quality, high uniformity, and stable nature of the material, the band structure flexibility of T2SLs enables novel detector architectures, making T2SLs probably the best realization of the material-by-design concept. Understanding the sophisticated physics of T2SLs is a crucial step towards the full development of this emerging technology. Commercial simulation tools successfully employed to design and optimize bulk HgCdTe detectors are not applicable to T2SLs, as complex quantum effects such as miniband transport and hopping between localized states cannot be described at a semiclassical level. In this project, we will address the sophisticated physics of carrier transport in T2SLs by means of the nonequilibrium Green#s function (NEGF) method, a state-of-the-art formalism for quantum device simulation. In short, the main objectives of the project are to provide the modeling tools to design superlattice detectors with higher operating temperatures, higher bandwidth, and improved detectivity. High-performance MWIR detectors are currently operated at cryogenic temperatures from 77 K to 140 K, which makes these devices expensive and bulky. Superlattice architectures with lower dark currents could provide high-performance at affordable costs. High-temperature operation would extend the operational life of the infrared system (detector plus cryogenic cooler), which is an important aspect in long U.S. Navy missions. The study of the mechanisms limiting the bandwidth in infrared detectors will provide guidance in the design and optimization of high-speed detector architectures for tracking hypersonic vehicles. Finally, a microscopic perspective on the origin of the excess noise in T2SLs will provide insight in the mechanisms limiting the detectivity of the system and will provide information about the material quality. The proposed research will be carriedout in collaboration with the Center of Semiconductor Modeling (CSM), a cooperative initiative established by Boston University andArmy Research Laboratory (ARL) to bring together government, academia, and industry in a collaborative fashion to address research opportunities.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 13, 2024
- Source ID
- N629092412059
Entities
People
- Francesco Bertazzi
Organizations
- Office of Naval Research
- Polytechnic University of Turin
- United States Navy