InAs/InAsSb Strained-Layer Superlattice Mid-Wavelength Infrared Detector for High-Temperature Operation.

Area of Science:

• Materials Science
• Semiconductor Physics
• Infrared Technology

Background:

• Mid-wavelength infrared (MWIR) detectors are crucial for various imaging applications.
• High-temperature operation is a significant challenge for current MWIR detector technologies.
• Strained-layer superlattices (SLS) offer tunable bandgaps for infrared absorption.

Purpose of the Study:

• To develop and characterize an InAs/InAsSb SLS detector and focal plane array (FPA) for high-temperature operation.
• To evaluate the performance metrics of the SLS detector, including quantum efficiency and dark current.
• To assess the potential of SLS detectors to surpass existing technologies at elevated temperatures.

Main Methods:

• Growth of InAs/InAsSb SLS using molecular beam epitaxy (MBE).
• Fabrication of detectors utilizing the nBn architecture.
• Comprehensive characterization of detector performance, including spectral response, quantum efficiency, and dark current.
• Testing of a 320x256 focal plane array (FPA) for imaging performance.

Main Results:

• The detector exhibited a cut-off wavelength of 5.5 µm and a peak external quantum efficiency of 56% at 140 K.
• A low dark current of 3.4 × 10⁻⁴ A/cm² was measured at 160 K.
• The FPA achieved a noise equivalent temperature difference (NETD) of ~10 mK at 80 K.
• Quantum efficiency increased with temperature up to 140 K, suggesting improved performance at higher operating temperatures.

Conclusions:

• The InAs/InAsSb SLS detectors show excellent potential for high-temperature MWIR applications.
• The developed SLS detectors can achieve performance comparable to InSb detectors at temperatures above 80 K.
• This technology enables advanced infrared imaging solutions for demanding operational environments.