Ab initio study of the trimethylaluminum atomic layer deposition process on carbon nanotubes—An alternative initial step

Electronic applications of carbon nanotubes (CNTs) require the deposition of dielectric films on the tubes while conserving their excellent electronic properties. In our density functional theory study, the authors use the trimethylaluminum (TMA) atomic layer deposition (ALD) as a model process for a CNT-functionalization. Since this functionalization relies on the presence of OH-groups, the CNTs are exposed to a water or oxygen pretreatment. The authors show that only CNTs with a single-vacancy defect are able to react with H₂O or O₂. Further, the defect is preferably saturated by oxygen. This leaves the CNT without the necessary hydroxyl groups for the first TMA addition. Therefore, the authors propose an alternative initial step after which a classical TMA ALD process can be performed on the CNT.