Graphene Nanomeshes – GANESH

The aim of the project GANESH is to design and fabricate via the bottom-up approach 2-dimensional graphene sheets containing a well-defined network of holes (nanomeshes) and to evaluate their optical and electronic properties through a combination of advanced experimental and theoretical studies.
The outstanding electronic, optical and mechanical properties of graphene have inspired the scientific community at both the fundamental and application levels. These perspectives for applications, ranging from high performance electronics, low power spintronics, to renewable energy, composite materials and biomedicine led to the establishment of the “Graphene Flagship” initiative by the European Union. However, along the way several key scientific issues have to be addressed and one of the main challenges in the field is the control and modification of graphene electronic properties; this concerns notably the controlled opening of a sizable bandgap. It is well known that when a material is reduced to nanoscale dimensions, the electronic confinement induces novel size-dependent properties. The reduction of one dimension of graphene down to the nanoscale leads to graphene nanoribbons while the reduction of the two dimensions leads to graphene quantum dots. Size reduction is not the only way to open a gap in graphene. A very appealing alternative to reduce the dimensionality of graphene consists in forming an ordered array of holes in a graphene sheet. This 2D-material, theoretically proposed in 2008, is called a Graphene Nanomesh or a Graphene Anti-dot Lattice. Early versions were fabricated in 2010 using the top-down approach (i.e. by templated etching of graphene). While the top-down approach remains predominant for the fabrication of GNMs, this approach does not permit a precise control of the hole sizes or of the graphene necks and their edges states. To achieve atomically precise nanomeshes, the bottom-up approach must be considered.
In this context, the objectives of the project GANESH are: i) to synthesize original organic precursors containing halogen connectors; ii) to deposit and polymerize them on a metal surface to form 2-dimensional covalent networks containing a well-defined network of holes in the structures; iii) to characterize them and to evaluate the optical and electronic properties of the GNMs by combining in situ and ex situ analyses with ab initio and semi-empirical calculations. To this end the project brings together four partners with complementary skills: chemistry, scanning probe microscopy, optics, electronics, theory and numerical simulations to achieve an ambitious program to engineer graphene materials exhibiting tailor-made optical and electronic properties.
The goal of the project is to advance the understanding of fundamental questions such as:
- Is it possible to precisely control the properties of graphene materials by controlling the structure at the atomic level?
- Is it possible to fabricate sufficiently large graphene nanomeshes via the bottom-up approach for potential future applications?
- How will the fundamental properties of GNMs vary with the presence of defects and doping elements?
In the context of a growing interest for the bottom-up synthesis of sp2 carbon nano-objects, the synthesis of particular graphene derivatives such as nanomeshes represents an exciting challenge from a chemistry point of view. From the physics point of view, the optical characterization and transport measurements propose studies at the forefront of research and susceptible to significantly impact the very active and highly competitive field of gaped-graphene materials. Such materials will interest the scientific community both at the theoretical and applicative level and it is almost certain that new collaborations will arise from this project to study new properties of GNMs including the transport behavior in a magnetic field, electrochemical properties, spintronics, or sensing.