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Band-structure-engineered high-gain LWIR photodetector based on a type-II superlattice
Arash Dehzangi1, Jiakai Li1, Manijeh Razeghi2
1Center for Quantum Devices, Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, 60208, USA.
Light, Science & Applications
|January 15, 2021
Summary
Researchers developed a high-gain, band-structure-engineered long-wavelength infrared (LWIR) photodetector using type-II superlattices. This novel LWIR photodetector achieves high responsivity and specific detectivity for advanced infrared applications.
Area of Science:
- Optoelectronics
- Materials Science
Background:
- Long-wavelength infrared (LWIR) photodetectors are crucial for applications like remote sensing, thermal imaging, and astronomy.
- Developing LWIR photodetectors with high detectivity and responsivity remains a key challenge.
Discussion:
- This study presents a novel high-gain LWIR heterojunction phototransistor engineered with type-II superlattices.
- The device exhibits a 1/e cut-off wavelength of 8.0 µm.
- Characterization at 77 K reveals unity optical gain at 90 mV bias and a dark current density of 3.2 × 10⁻⁷ A/cm².
Key Insights:
- The phototransistor achieves a saturated optical gain of 276 at 220 mV bias.
- This corresponds to a responsivity of 1284 A/W and a specific detectivity of 2.34 × 10¹³ cm Hz¹/² /W at ~6.8 µm.
- Band structure engineering is demonstrated as an effective approach for high-performance LWIR photodetector design.
Outlook:
- The developed type-II superlattice LWIR device signifies a pathway towards next-generation infrared detection systems.
- Further research can explore optimizing band structure engineering for even higher performance and broader LWIR applications.
