Reversible n-Type Doping of Graphene by H2O-Based Atomic-Layer Deposition and Its Doping Mechanism

The pre-H2O treatment and Al2O3 film growth under a two-temperature-regime mode in an oxygen-deficient atomic layer deposition (ALD) chamber can induce n-type doping of graphene, with the enhancement of electron mobility and no defect introduction to graphene. The main mechanism of n-type doping is surface charge transfer at graphene/redox interfaces during the ALD procedure. More interestingly, this n-type doping of graphene is reversible and can be recovered by thermal annealing, similar to hydrogenated graphene (graphane). This technique utilizing pre-H2O treatment and an encapsulated layer of Al2O3 achieved in an oxygen,deficient ALD chamber provides a simple and novel route to fabricate n-type doping of graphene.