Atomic-Scale Tuning of Graphene/Cubic SiC Schottky Junction for Stable Low-Bias Photoelectrochemical Solar-to-Fuel Conversion.

Hao Li,Lizhi Zhang,Mikael Syväjärvi,Roger I G Uhrberg,Weimin Wang,Jianwu Sun,Rositsa Yakimova,Alexei A Zakharov,Lars Hultman,Huan Shang,Yuchen Shi,Jun Lu

doi:10.1021/acsnano.0c00986

Hao Li, Lizhi Zhang + Show 10 more

Open Access

https://doi.org/10.1021/acsnano.0c00986

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Abstract

Engineering tunable graphene–semiconductor interfaces while simultaneously preserving the superior properties of graphene is critical to graphene-based devices for electronic, optoelectronic, biomedical, and photoelectrochemical applications. Here, we demonstrate this challenge can be surmounted by constructing an interesting atomic Schottky junction via epitaxial growth of high-quality and uniform graphene on cubic SiC (3C-SiC). By tailoring the graphene layers, the junction structure described herein exhibits an atomic-scale tunable Schottky junction with an inherent built-in electric field, making it a perfect prototype to systematically comprehend interfacial electronic properties and transport mechanisms. As a proof-of-concept study, the atomic-scale-tuned Schottky junction is demonstrated to promote both the separation and transport of charge carriers in a typical photoelectrochemical system for solar-to-fuel conversion under low bias. Simultaneously, the as-grown monolayer graphene with an extremely high conductivity protects the surface of 3C-SiC from photocorrosion and energetically delivers charge carriers to the loaded cocatalyst, achieving a synergetic enhancement of the catalytic stability and efficiency.

Highlights

Engineering tunable graphene−semiconductor interfaces while simultaneously preserving the superior properties of graphene is critical to graphene-based devices for electronic, optoelectronic, biomedical, and photoelectrochemical applications
For graphene layers that are produced through chemical exfoliation of graphite or chemical vapor deposition on metals, their superior properties are deteriorated during the required transfer process to semiconductor substrates, often with residues of processing chemicals
A considerable advantage of this technique is that graphene can be in situ produced, without etchant chemicals, on a large area with extremely high quality and uniformity, ensuring the high quality of the graphene−semiconductor junction structure

Summary

Introduction

Engineering tunable graphene−semiconductor interfaces while simultaneously preserving the superior properties of graphene is critical to graphene-based devices for electronic, optoelectronic, biomedical, and photoelectrochemical applications We demonstrate this challenge can be surmounted by constructing an interesting atomic Schottky junction via epitaxial growth of high-quality and uniform graphene on cubic SiC (3C-SiC). 3C-SiC interface, with a tunable barrier and the built-in electric field, enables us to systematically control and comprehend the interfacial electronic properties and transport mechanisms of graphene-based devices Benefiting from these merits, the atomically sharp graphene/3C-SiC Schottky junction is demonstrated to tackle three great challenges of photoelectrochemical catalysis: the limited light absorption, the undesirable charge recombination, and instability of photoelectrodes.[13−15] As a proof-of-concept study, the junction structure described exhibits a synergetic enhancement of both the stability and the efficiency of photoelectrochemical solar-to-fuel conversion

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