Lateral Structured Phototransistor Based on Mesoscopic Graphene/Perovskite Heterojunctions

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Organometal halide perovskites offer excellent optical properties and charge carrier mobility, making them promising for photodetection and solar cells.
• Existing perovskite photodetectors benefit from high optical absorption and quantum efficiency, impacting responsivity and specific detectivity.

Purpose of the Study:

• To develop a novel lateral phototransistor utilizing a mesoscopic graphene/perovskite heterojunction.
• To investigate the charge transfer mechanisms and performance of the hybrid photodetector.

Main Methods:

• Fabrication of a lateral phototransistor using mesoscopic graphene nanowall/perovskite heterojunctions.
• Characterization of the device's photoelectric properties, including responsivity and specific detectivity.
• Analysis of charge transfer dynamics via luminescence spectra and proposed photoconductive mechanisms.

Main Results:

• The graphene/perovskite phototransistor demonstrated high performance with a responsivity of 2.0 × 10³ A/W and specific detectivity of 7.2 × 10¹⁰ Jones.
• Efficient hole transfer from perovskite to graphene was observed, with graphene acting as a hole collector and transport channel.
• Perovskite passivation and graphene photogating effects were identified as key contributors to the device's performance.

Conclusions:

• The developed graphene/perovskite phototransistor shows significant potential for advanced photodetection applications.
• The study highlights the effectiveness of graphene-perovskite heterojunctions for efficient charge separation and transport.
• This work offers new strategies for utilizing perovskite films in high-performance photodetector devices.