Atomic layer deposition for graphene device integration

Graphene is a two dimensional material with extraordinary properties, which make it an interesting material for many optical and electronic devices. The integration of graphene in these devices often requires the deposition of thin dielectric layers on top of graphene. Atomic layer deposition (ALD) is the method of choice to deposit these layers due to its ability to deposit ultra-thin, high quality films with sub-monolayer thickness control. ALD on graphene however, is a challenge due to the lack of reactive surface sites on graphene. This leads to the selective growth on grain boundaries, wrinkles and defect sites present in the graphene. In this review an overview of the different methods to achieve uniform deposition of ALD on graphene is presented. The advantages and disadvantages of each method are discussed from the perspective of ALD together with the opportunities for further research. Special emphasis is given to the recent advancements in the understanding of the ALD process conditions and their influence on the deposition uniformity on graphene. Particularly, improving the quality of the dielectric layers deposited by ALD while maintaining the pristine properties of graphene, will prove vital for the device integration of graphene.