Synthesis of Wet‐Chemically Prepared Porous‐Graphene Single Layers on Si/SiO2 Substrate Increasing the Photoluminescence of MoS2 in Heterostructures

Yiqing Wang,Siegfried Eigler,Christof Neumann,Oisín Garrity,Marleen Hußmann,Andrey Turchanin,Qing Cao,Yalei Hu,Patryk Kusch

doi:10.1002/admi.202100783

Yiqing Wang, Siegfried Eigler + Show 7 more

Open Access

https://doi.org/10.1002/admi.202100783

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Abstract

AbstractWet‐chemical generation of pores in graphene is a challenging synthetic task. Although graphene oxide is available in large quantities and chemically diverse, extended lattice defects already present from synthesis hamper the controlled growth of pores. However, membrane, energy, or nanoelectronic applications essentially require uniform pores in applications. Here, oxo‐functionalized graphene (oxoG), a type of graphene oxide with a controlled density of vacancy defects, is used as starting material. Pores in graphene are generated from potassium permanganate treated oxoG and heating from room temperature to 400 °C. With etching time, the size of pores increases and pore‐diameters of, for example, 100–200 nm in majority become accessible. The experiments are conducted on the single‐layer level on Si/SiO2 wafers. Flakes remain stable on the µm scale and do not fold. The process leads to rims of pores, which are functionalized by carbonyl groups in addition to hydroxyl and carboxyl groups. In addition, it is found that heterostructures with intrinsically n‐doped MoS2 can be fabricated and photoluminescence (PL) measurements reveal a 10‐fold increased PL. Thus, graphene with pores is a novel highly temperature‐stable electron‐accepting 2D material to be integrated into van der Waals heterostructures.

Highlights

Wet-chemical generation of pores in graphene is a challenging synthetic task
The process leads to rims of pores, which are functionalized by carbonyl groups in addition to hydroxyl and carboxyl groups
We demonstrated the fabrication of graphene with circular pores on the 100 nm scale deposited on Si/SiO2 surface by annealing of oxo-functionalized and potassium permanganate treated graphene flakes at 400 °C

Summary

Introduction

Wet-chemical generation of pores in graphene is a challenging synthetic task. graphene oxide is available in large quantities and chemically diverse, extended lattice defects already present from synthesis hamper the controlled growth of pores. Thereby, functionalization of deposited graphene can in principle occur on the surface or at the graphene with pores is a novel highly temperature-stable electron-accepting rim of flakes. The formation of larger pores is not possible, since flakes start to disintegrate.[28,32,33,34,35] graphene oxide with extended lattice defects conceptionally can’t be considered as a precursor for generating graphene with pores of reasonable lateral dimensions, of tens to hundreds of nm (Table S1, Supporting Information). By controlling the reaction conditions, it is possible to gain a certain control over the formation of pores with diameters between 100–200 nm in majority Those pore-graphene materials are highly temperature stable since they are synthesized at 400 °C. We report that the amplitude of the photoluminescence (PL) signal of MoS2 enhances 10-times

Results and Discussion

Conclusion

Data Availability Statement