Oxidized eutectic gallium–indium (EGaIn) nanoparticles for broadband light response in a graphene-based photodetector

Abstract

Graphene is considered to be a valuable material in the field of photodetection due to its ultra-high electron mobility. However, its weak light absorption, short carrier lifetime and lack of gain mechanism limit the light responsivity of graphene at the magnitude of mA W⁻¹. Herein, based on the oxidation characteristics of eutectic gallium–indium (EGaIn) alloy and the adoption of low-cost physical vapor deposition methods, we develop nanoparticles with gradient changes in elements to solve the drawback of common quantum dots of a narrow response band, fabricating a composite nanostructure of suspended graphene and oxidized EGaIn nanoparticles. The photodetector achieves wide-spectrum and high-performance detection from ultraviolet to near-infrared, with a responsivity enhancement of three order magnitude compared to that of pristine graphene. Then, the enhancement mechanism is analysed through structural characterization and control experiments, proving the dominant effect of oxidized nanoparticles on improving the responsivity and response band. This paper expands the application of EGaIn in the field of photoelectric detection and offers new idea for constructing high-performance quantun-dot based photodetectors.