A Photovoltaic-Integrated Broadband Photodetector Based on Vertically-Stacked Lateral-Aligned Nanowire Arrays

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Vertically-stacked planar structures for integrated solar cells and photodetectors suffer from performance competition.
• Achieving broadband absorption in integrated devices remains a challenge.

Purpose of the Study:

• To propose and investigate a photovoltaic-integrated broadband photodetector using vertically-stacked lateral-aligned III-V nanowire arrays.
• To enhance light absorption and device performance through a staggered arrangement.

Main Methods:

• Fabrication of vertically-stacked lateral-aligned III-V nanowire arrays (GaAs and InAs).
• Utilizing a staggered configuration to reduce interference between solar cell and photodetector functions.
• Employing Mie scattering from GaAs nanowires and light trapping by InAs nanowires to enhance broadband absorption.

Main Results:

• The staggered arrangement enables broadband strong absorption from UV to infrared.
• Photovoltaic-integrated InAs nanowire photodetectors showed a 90% increase in photocurrent density and 93% increase in responsivity at 1400 nm compared to single-layer devices.
• Improved conversion efficiency of the integrated GaAs nanowire solar cell.

Conclusions:

• The proposed staggered nanowire design effectively overcomes the limitations of planar structures.
• This approach leads to enhanced broadband absorption and improved performance for integrated photodetectors and solar cells.
• The work offers a pathway for developing self-powered miniaturized broadband photodetectors.