Opening the band gap of graphene through silicon doping for improved performance of graphene/GaAs heterojunction solar cells

TL;DR

This study demonstrates that silicon doping of monolayer graphene opens its band gap and enhances the performance of graphene/GaAs heterojunction solar cells, leading to a significant increase in power conversion efficiency.

Contribution

The paper presents a novel method of silicon doping in monolayer graphene to open its band gap and improve solar cell efficiency, supported by experimental and theoretical evidence.

Findings

Silicon doping introduces a 0.28 eV band gap in graphene.

SiG/GaAs solar cells show 33.7% higher efficiency than undoped graphene devices.

Doping increases work function and interface quality, enhancing device performance.

Abstract

Graphene has attracted increasing interests due to its remarkable properties, however, the zero band gap of monolayer graphene might limit its further electronic and optoelectronic applications. Herein, we have successfully synthesized monolayer silicon-doped graphene (SiG) in large area by chemical vapor deposition method. Raman spectroscopy and X-ray photoelectron spectroscopy measurements evidence silicon atoms are doped into graphene lattice with the doping level of 3.4 at%. The electrical measurement based on field effect transistor indicates that the band gap of graphene has been opened by silicon doping, which is around 0. 28 eV supported by the first-principle calculations, and the ultraviolet photoelectron spectroscopy demonstrates the work function of SiG is 0.13 eV larger than that of graphene. Moreover, the SiG/GaAs heterostructure solar cells show an improved power conversion efficiency of 33.7% in average than that of graphene/GaAs solar cells, which are attributed to the increased barrier height and improved interface quality. Our results suggest silicon doping can effectively engineer the band gap of monolayer graphene and SiG has great potential in optoelectronic device applications.