Gradient Doping Triggers Flexo-Pyroelectric Effects toward Self-Powered Broadband Photodetection and Smart...

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Broadband self-powered photodetectors (PDs) are crucial for intelligent sensing.
• Achieving simultaneous deep-ultraviolet to near-infrared (DUV-NIR) detection and high responsivity in PDs is challenging.

Purpose of the Study:

• To engineer a controllable flexoelectric polarization field to enhance photodetector performance.
• To develop a self-powered photodetector with ultrabroadband spectral response and high responsivity.

Main Methods:

• Designed a compressive strain gradient to create a flexoelectric polarization field.
• Utilized the flexo-pyroelectric effect by synergizing flexoelectricity with the pyroelectric effect.
• Fabricated a graded p-Si/n-ZnO:Ga heterojunction photodetector.

Main Results:

• Achieved an ultrabroadband spectral response from 200 to 1550 nm.
• Obtained a peak transient responsivity of 2.24 A W^-1 and external quantum efficiency >100%.
• Demonstrated quantitative identification of environmental pollutants using the nonlinear optical response.

Conclusions:

• The flexo-pyroelectric effect significantly enhances the built-in electric field and photoresponse.
• The developed photodetector is a promising candidate for next-generation intelligent self-powered sensing systems.
• This work offers a general design principle for advanced optoelectronic devices.