Monolithically Integrated THz Detectors Based on High-Electron-Mobility Transistors.

Area of Science:

• Terahertz (THz) technology
• Semiconductor device physics
• Optoelectronics

Background:

• Terahertz direct detectors are crucial for various imaging and sensing applications.
• Existing detectors often face limitations in sensitivity, noise performance, or scalability.
• AlGaN/GaN high electron mobility transistors (HEMTs) offer promising material properties for high-frequency applications.

Purpose of the Study:

• To present novel THz direct detectors based on AlGaN/GaN HEMTs.
• To demonstrate state-of-the-art performance at room temperature.
• To showcase the scalability of these detectors for terahertz focal plane arrays (FPAs).

Main Methods:

• Monolithic integration of AlGaN/GaN HEMTs with diverse antenna designs.
• Fabrication of single-pixel THz detectors and a two-dimensional THz FPA.
• Theoretical and experimental characterization of detector performance across a broad frequency range (0.1–1.5 THz).

Main Results:

• Achieved excellent optical sensitivity (>20 mA/W up to 1 THz) and low noise-equivalent power (NEP < 100 pW/Hz).
• Demonstrated a record low optical NEP of <10 pW/Hz at 175 GHz for single detectors.
• Successfully realized and characterized a functional THz FPA operating from 0.1–1.1 THz.

Conclusions:

• AlGaN/GaN HEMT-based THz detectors offer superior performance, including high sensitivity and low NEP at room temperature.
• The detector architecture is readily scalable for practical terahertz focal plane array applications.
• These findings represent a significant advancement in THz detection technology for future scientific and commercial uses.