High operating temperature mid-wavelength infrared detectors based on InAs/InAsSb superlattices with electron block...

Area of Science:

• Solid State Physics
• Optoelectronics
• Materials Science

Background:

• Mid-wavelength infrared (MWIR) detectors are crucial for various applications.
• High operating temperatures and low dark current are key challenges in MWIR detector development.
• Superlattice structures offer tunable bandgaps for optimized infrared detection.

Purpose of the Study:

• To demonstrate a high operating temperature mid-wavelength infrared detector.
• To investigate the impact of electron block interfacial graded doping on detector performance.
• To assess the potential for room-temperature operation of InAs/InAsSb superlattice detectors.

Main Methods:

• Fabrication of a pBn infrared detector using InAs/InAsSb superlattices.
• Incorporation of an electron block interfacial graded doping layer.
• Characterization of photodetector performance including quantum efficiency, responsivity, detectivity, and dark current density at various temperatures.
• Comparison of experimental dark current with the Rule 07 prediction.

Main Results:

• Saturated quantum efficiency observed from 77 K to 250 K under zero bias.
• Peak detectivity of 1.24 × 10^12 cm·Hz^1/2/W achieved at 150 K with a cutoff wavelength of 5.0 µm.
• Dark current density significantly reduced by interfacial graded doping, outperforming Rule 07 predictions above 190 K.
• Extended cutoff wavelength to 6.2 µm at 290 K with a specific detectivity of 9.87 × 10^9 cm·Hz^1/2/W.

Conclusions:

• The demonstrated InAs/InAsSb pBn infrared detector exhibits high operating temperature capabilities.
• Interfacial graded doping effectively suppresses dark current, enhancing device performance.
• The detector shows significant potential for practical, high-performance room-temperature infrared sensing applications.