Quasi-planar InGaAsSb p-B-n photodiodes for spectroscopic sensing.

Area of Science:

• Semiconductor Physics
• Optoelectronics
• Materials Science

Background:

• Development of sensitive photodetectors is crucial for various applications, including chemical sensing and optical communications.
• Low-power, zero-bias operation is desirable for miniaturized and energy-efficient devices.

Purpose of the Study:

• To design and characterize an Indium Gallium Arsenide Antimonide (InGaAsSb) p-B-n photodiode.
• To evaluate its performance for zero-bias, low-power detection applications, particularly for sensing low-concentration biomarkers.

Main Methods:

• Growth of InGaAsSb heterostructures using molecular beam epitaxy (MBE).
• Fabrication of quasi-planar photodiodes with a specific cut-off wavelength.
• Characterization of responsivity, noise power, and specific detectivity (D*) at various temperatures.

Main Results:

• Achieved maximum responsivity of 1.05 A/W at 2.0 µm under zero bias.
• Measured specific detectivity (D*) of 9.4 × 10^10 Jones at room temperature.
• Maintained D* > 1 × 10^10 Jones up to 380 K.
• Demonstrated detection of optical powers as low as 40 pW without complex stabilization.

Conclusions:

• The InGaAsSb photodiode exhibits excellent performance for zero-bias, low-power detection.
• Its high sensitivity and broad operating temperature range make it suitable for miniaturized biomarker detection systems.
• The device shows significant potential for applications requiring sensitive optical measurements without active cooling or phase-sensitive techniques.