Self-powered MSM solar-blind AlGaN photodetector realized by in-plane polarization modulation

Area of Science:

• Optoelectronics
• Semiconductor Devices
• Materials Science

Background:

• Solid-state self-powered ultraviolet (UV) detection is crucial for long-term operational applications.
• Conventional metal-semiconductor-metal (MSM) UV photodetectors (PDs) face limitations due to symmetric Schottky contacts, hindering self-powered operation.
• The need for efficient, self-powered UV detection without external bias is a significant challenge in optoelectronics.

Purpose of the Study:

• To develop a self-powered, solar-blind UV photodetector (PD) with enhanced performance.
• To investigate a lateral pn junction architecture in an MSM-type UV-PD to achieve self-powered operation.
• To demonstrate efficient carrier separation and enhanced photoresponsivity at zero external bias.

Main Methods:

• Fabrication of a metal-semiconductor-metal (MSM) UV photodetector (PD) utilizing a lateral pn junction architecture.
• Characterization of the UV-PD's performance, including cutoff wavelength, photo/dark current ratio, and responsivity.
• Utilized Technology Computer-Aided Design (TCAD) simulations to analyze internal electric field and carrier distributions for mechanism investigation.

Main Results:

• Achieved a self-powered, solar-blind UV-PD with a cutoff wavelength of 280 nm.
• Demonstrated a high photo/dark current ratio exceeding 10^5 and a responsivity of 425.13 mA/W at -10 V.
• Observed efficient carrier separation and enhanced photoresponsivity at zero external bias due to a large built-in electric field.

Conclusions:

• The lateral pn junction architecture effectively enables self-powered operation in MSM-type UV photodetectors (PDs).
• The developed solar-blind UV-PD exhibits excellent performance metrics, suitable for various demanding applications.
• TCAD simulations confirmed the mechanism of self-powered UV photodetection, highlighting the role of the built-in electric field.