InAs on GaAs Photodetectors Using Thin InAlAs Graded Buffers and Their Application to Exceeding Short-Wave Infrared...

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Short-wave infrared (SWIR) detectors are crucial for applications like IoT, ADAS, and gas sensing.
• Current Indium Gallium Arsenide (InGaAs) photodetectors have limited spectral range (up to 1.7 μm cutoff).
• Expanding SWIR detection capabilities is vital for advanced technological applications.

Purpose of the Study:

• To develop an Indium Arsenide (InAs) p-i-n photodetector with extended SWIR range.
• To investigate the performance of InAs photodetectors grown on a GaAs substrate.
• To demonstrate the photodetector's utility in real-world imaging applications.

Main Methods:

• Epitaxial growth of an InAs photodetector on a GaAs (001) substrate.
• Inclusion of Indium Aluminum Arsenide (InxAl1-xAs) graded and Aluminum Arsenide (AlAs) buffer layers.
• Characterization of photodetector performance at room temperature, including spectral response and detectivity.

Main Results:

• The fabricated InAs photodetector operates across a broad SWIR range (approx. 1.5-4 μm).
• Achieved a high detectivity (D*) of 1.65 × 10^8 cm·Hz^1/2·W^-1 at 3.3 μm.
• Successfully demonstrated performance through Sherlock Holmes mapping images at room temperature.

Conclusions:

• The developed InAs photodetector offers enhanced SWIR detection capabilities beyond traditional InGaAs devices.
• The device shows significant potential for improved gas sensing, IoT, and ADAS applications.
• Room-temperature operation and high detectivity make this photodetector a promising candidate for advanced infrared imaging.