InAs/InAsSb Strain-Balanced Superlattices for Longwave Infrared Detectors.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Semiconductor Physics

Background:

• Type-II superlattices (T2SLs) based on InAs/InAsSb offer potential for high-temperature operation.
• These materials are relevant for longwave infrared (LWIR) detection, crucial for applications like health monitoring (e.g., CH4 and C2H6 detection).

Purpose of the Study:

• To theoretically investigate InAs/InAsSb T2SLs grown on GaSb buffer layers and GaAs substrates.
• To determine optimal structural parameters for LWIR detector applications.

Main Methods:

• Theoretical calculations using the 8 × 8 k·p method.
• Analysis of electron and heavy hole probability distribution and effective masses.
• Comparison of theoretical bandgap and spectral response with experimental results.

Main Results:

• Increased wave function overlap with decreasing superlattice (SL) period thickness.
• Optimal structures for LWIR detectors identified with periods below 15 nm.
• Theoretical energy bandgap values show good agreement with experimental findings.

Conclusions:

• InAs/InAsSb T2SLs with periods <15 nm are promising for LWIR detector fabrication.
• The study provides a theoretical framework validated by experimental data for designing advanced infrared sensors.