Long-Wave Infrared HgTe Quantum Dot Photoconductors with Optical Enhancement.

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Quantum dots (QDs) offer tunable optical properties for infrared detection.
• Mercury telluride (HgTe) QDs are promising for long-wave infrared (LWIR) applications.

Purpose of the Study:

• To investigate HgTe quantum dots for interband absorption-based LWIR detection.
• To optimize HgTe QD films and device structures for improved performance.

Main Methods:

• Fabrication of HgTe QD films on interdigitated electrodes.
• Characterization of optical constants, photoluminescence, mobility, and carrier lifetime.
• Integration with metal-insulator-metal structures and nanoantennas.

Main Results:

• Intrinsic HgTe QD films processed with HgCl2 solutions showed best performance.
• Photoresponse extended beyond 8 μm at 85 K.
• Metal-insulator-metal structures with nanoantennas increased responsivity and detectivity by ~20x at 8.5 μm.
• Achieved detectivity of 1.47 × 10^10 Jones and EQE of 12.5%.

Conclusions:

• HgTe QDs are viable for LWIR detection, with performance limited by absorption coefficient and exciton lifetime.
• Advanced device architectures significantly enhance infrared detection capabilities.
• Optimized HgTe QD films and nanostructures pave the way for high-performance LWIR photodetectors.