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Research

Research

Research

Summary

Specifically, this program offers the following key aspects: i) theoretical models of defects to assist with a better understanding of defect formation in T2SLs; ii) improved material growth technologies with the capabilities for low-cost and volume production; iii) detailed materials knowledge for next generation IR devices; vi) possibilities to offer low-cost and high-performance IR lasers and detectors; and v) user-friendly software based on the new practical device model taking into account the effects of defects. The attainment of all the objectives of this program will help maintain US leadership in the area of T2SLs research and development.

Antimony-based type-II superlattice (T2SLs) offer advantages for MWIR (Midwave Infrared) and LWIR (Long-Wave Infrared) laser and detector applications due to their broad bandgap tunability and material uniformity. The performance of T2SL IR detectors is predicted to be superior to that of MCT (HgCdTe) IR detectors. Recent intensive research on novel T2SL structures has demonstrated significant progress and interesting device physics, but the predicted high performance has yet to be realized as T2SL IR detectors are still limited by defects and interface-related traps. A thorough understanding of defect physics, growth processes, and detector theory is crucial for the suppression of defect formation and their adverse effects.

Given the motivation for this project, the main objectives are:

  • Identify and understand the origin of point defects, line defects, interfacial traps, and surface states in T2SL structures through experimental studies closely coupled to theoretical modeling.
  • Correlate defect properties with device performance as a function of operating temperature, including minority carrier lifetime, detector noise, dark current, breakdown voltage, shunt resistance, and surface recombination.
  • Examine novel MBE and MOCVD growth methods and passivation techniques that eliminate and or mitigate defects in InAs/GaSb, InAs/InGaSb, and InAs/InAsSb T2SLs
  • .
  • Develop a comprehensive device physics model that includes extrinsic material properties to accurately predict device performance and provide vital device design rules.

Funding

U.S. Army Multidisciplinary University Research Initiative Program through the University of Illinois at Urbana-Champaign

Timeline

November 2010 — December 2013