Before we take a look at graphene conductivity, it’s worth it to note why it is such an important topic.
Ever since graphene’s Nobel Prize-winning discovery in 2004, the combination of research and race to translate its highly unusual properties into practice has revealed many promising applications. It is superconductive, biocompatible, flexible, and operates well even at nano-scales around 10 nm.
For this reason, many companies and research institutes work tirelessly to develop graphene’s electrical uses.
To answer this question, it is at first necessary to understand graphene’s structure. Graphene is a two-dimensional layer of hexagonal carbon lattices that can in theory stretch indefinitely.
The flat surface poses little resistance to the passing electrons, meaning the material has extremely high electron mobility. The electrons usually move in a straight line from source to sink; not encountering any obstacles.
However, this structure also means that graphene’s valence and conduction bands overlap. A result of the overlap is an effective lack of band gap within the material, which could be responsible for semi-conductive properties.
Graphene’s extremely high electron mobility (exceeding 15 000 cm/Vs) makes it a highly interesting material for electronics and the community is trying to introduce a band gap by either creasing the material (introducing physical obstacles) or by adding chemical additives that disturb the uniform surface in a controlled manner.
The promise of graphene semi-conductor technology is essentially three-fold: super-efficient semi-conductors, quantum computation, and silica replacement.
Graphene is much more conductive than copper and has higher electron mobility. If a band gap could be introduced, a much more efficient technology could be created.
Graphene is a nano-superconductor. This combination of properties allows for the manifestation of quantum effects on the electrons. Entangled particles, such as those in superpositions before the collapse of the wave function, could be used to carry out quantum operations.
As the development of IT, in combination with the Moore’s law, drives computational technology towards higher and higher efficiency, it also necessarily creates the need for smaller parts. Graphene is well functional around 10 nm, which is one-half of silica’s lower limits; thus being a potential replacement of silica-based computation.
When it comes to the development of supercapacitors and superconductor products, Graphene’s exceptional electrical properties lend it a spot in the limelight.
Supercapacitors can be considered middle ground between conventional batteries and capacitors. While a battery charges slowly over time and discharges in the same manner, a capacitor charges very quickly and discharges quickly.
It a nutshell, supercapacitors charge like capacitors but discharge like batteries. This means they charge quickly and give electricity slowly. For this reason, supercapacitors may be a solution to fast-charging electric cars or smartphones. One challenge for the widespread consumer application of graphene supercapacitors is their comparatively lower energy density.
Graphene’s superconductive properties find a practical application in conductive inks. Since graphene’s electron mobility and conductivity depend very little on surrounding temperature, it is the ideal material for all-purpose conductive inks.
In order for the ink to conduct well, graphene needs to be deposited carefully and aligned onto a plane. This is also the reason why e.g. graphene wiring is still being developed.
It makes sense that a new material needs time before all of its properties can come to full fruition. However, once the technicalities are sorted out, it will be possible print precise systems with conductive ink or perform extra-fast calculations with graphene-based superconductive semi-conductors.