Solar-blind photodetectors for harsh electronics

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Devices

Background:

• Deep ultraviolet (DUV) photodetectors are crucial for various applications, but often face limitations in extreme conditions.
• Aluminum nitride (AlN) is a promising material for DUV applications due to its wide bandgap and inherent stability.
• Developing robust photodetectors for harsh environments, such as high temperatures and radiation, remains a significant challenge.

Purpose of the Study:

• To demonstrate the efficacy of AlN thin films on Si(100) substrates for fabricating solar-blind photodetectors (PDs).
• To evaluate the performance characteristics of these AlN PDs under challenging operational conditions, including elevated temperatures and proton irradiation.
• To assess the potential of AlN metal-semiconductor-metal (MSM) PDs for next-generation DUV sensing in demanding environments.

Main Methods:

• Fabrication of AlN thin films on Si(100) substrates.
• Characterization of AlN metal-semiconductor-metal (MSM) photodetector performance.
• Testing under varying temperatures (up to 300°C) and proton fluences (up to 10^13 cm^-2 of 2-MeV protons).

Main Results:

• Achieved solar-blind photodetectors with extremely low dark current (~1 nA) even at bias voltages exceeding 200 V.
• Demonstrated excellent temperature tolerance up to 300°C and high radiation hardness up to 10^13 cm^-2 of 2-MeV proton fluences.
• Observed fast photoresponse times: ~110 ms rise time and ~80 ms fall time at 5 V bias.

Conclusions:

• AlN thin films on Si(100) substrates are highly suitable for creating robust solar-blind photodetectors.
• The developed AlN MSM PDs exhibit superior performance metrics, including low dark current, high temperature tolerance, and radiation hardness.
• These findings highlight the significant potential of AlN MSM PDs for advanced DUV detection applications in harsh environments.