Seeding Atomic Layer Deposition of Alumina on Graphene with Yttria
2015
Dahal, Arjun | Addou, Rafik | Azcatl, Angelica | Coy-Diaz, Horacio | Lu, Ning | Peng, Xin | de Dios, Francis | Kim, Jiyoung | Kim, Moon J. | Wallace, Robert M. | Batzill, Matthias
Integrating graphene into nanoelectronic device structure requires interfacing graphene with high-κ dielectric materials. However, the dewetting and thermal instability of dielectric layers on top of graphene makes fabricating a pinhole-free, uniform, and conformal graphene/dielectric interface challenging. Here, we demonstrate that an ultrathin layer of high-κ dielectric material Y₂O₃ acts as an effective seeding layer for atomic layer deposition of Al₂O₃ on graphene. Whereas identical Al₂O₃ depositions lead to discontinuous film on bare graphene, the Y₂O₃ seeding layer yields uniform and conformal films. The morphology of the Al₂O₃ film is characterized by atomic force microscopy and transmission electron microscopy. C-1s X-ray photoemission spectroscopy indicates that the underlying graphene remains intact following Y₂O₃ seed and Al₂O₃ deposition. Finally, photoemission measurements of the graphene/SiO₂/Si, Y₂O₃/graphene/SiO₂, and Al₂O₃/Y₂O₃/graphene/SiO₂ interfaces indicate n-type doping of graphene with different doping levels due to charge transfer at the interfaces.
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