The Need

High-sensitivity detection in the mid-wave and long-wave infrared (MWIR/LWIR) remains constrained by detector noise, limited gain, and manufacturing challenges. While HgCdTe avalanche photodiodes can deliver excellent performance, they suffer from high cost, low yield, and limited manufacturability. Existing APD approaches in these wavelength ranges struggle with excess noise, dark current, and complex heterostructure designs. There is a clear need for a scalable, low-noise MWIR/LWIR APD technology compatible with mature semiconductor manufacturing.

The Technology

OSU engineers have developed a novel separate-absorption-and-multiplication avalanche photodiode architecture optimized for MWIR and LWIR operation. It combines a long-wavelength infrared absorber with a low-noise multiplication region engineered for efficient carrier transfer and avalanche gain. The device architecture enables high internal gain while suppressing dark current and excess noise, without relying on complex bandgap grading. The approach leverages well-established material platforms to achieve performance advantages previously limited to specialized detector technologies.

Commercial Applications

• Long-range MWIR/LWIR LiDAR and free-space optical ranging
• Low-light infrared imaging and sensing systems
• Infrared spectroscopy and environmental monitoring
• Defense, security, and aerospace infrared detection platforms

Benefits/Advantages

• Lower noise at high gain
• Simplified heterostructure design
• Compatibility with III–V foundry manufacturing
• Flexible wavelength coverage