Properties of graphene/borophene etc.

[sbrothy]

In a recent paper about borophene it shows promise for detecting hydrogen cyanide gas [1903.11304 - Review of Borophene and it's Potential Applications]. My question may seem rather simpleminded but I'm under no illusions regarding my physics knowledge so please bear with me:

Did anyone consider that perhaps layers of 3, 5, 7 (etc.) atoms thickness could have other properties? Does this concept have a name or does it simply not make any sense?

 

[Cthugha]

Usually that would not be considered as a layer of larger thickness, but a structure consisting of several layers.

For 2D materials, these different structures are usually called monolayers or bilayers. They usually show very different properties. For example for TMDCs, a monolayer may be a direct band gap semiconductor, while a bilayer may show an indirect bandgap.

When considering multilayer structures, there are several concepts which carry different names. If you want to consider a structure made out of several monolayers of different materials, this goes by the name of van der Waals heterostructures. If you want to consider a multilayer system of the same material, where the individual layers are geometrically different (e.g. rotated with respect to each other - this also has a huge influence on the properties of the system), this goes by the name of twisted monolayers or Moire superlattices.

However, I do not know to which extent this has been studied in Borophene.

 

[sbrothy]

Very informative. Thank you. I guess I was thinking monolayers, or rather bi- or maybe even polylayers (if again that makes any sense). I'm not surprised that they exhibit different properties. Fascinating.

 

[sbrothy]

Or rather multilayers as you say.