title: Atomic Layer Deposition of Hafnium(IV) Oxide on Graphene Oxide: Probing Interfacial Chemistry and Nucleation by using X-ray Absorption and Photoelectron Spectroscopies.
abstract: Interfacing graphene with metal oxides is of considerable technological importance for modulating carrier density through electrostatic gating as well as for the design of earth-abundant electrocatalysts. Herein, we probe the early stages of the atomic layer deposition (ALD) of HfO2on graphene oxide using a combination of C and O K-edge near-edge X-ray absorption fine structure spectroscopies and X-ray photoelectron spectroscopy. Dosing with water is observed to promote defunctionalization of graphene oxide as a result of the reaction between water and hydroxyl/epoxide species, which yields carbonyl groups that further react with migratory epoxide species to release CO2. The carboxylates formed by the reaction of carbonyl and epoxide species facilitate binding of Hf precursors to graphene oxide surfaces. The ALD process is accompanied by recovery of the π-conjugated framework of graphene. The delineation of binding modes provides a means to rationally assemble 2D heterostructures.
authors.affiliation: Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012 (USA).|Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843-3003 (USA).
authors.forename: Theodore E G
authors.initials: TEG
authors.lastname: Alivio
authors.affiliation: Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012 (USA).|Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843-3003 (USA).
authors.forename: Luis R
authors.initials: LR
authors.lastname: De Jesus
authors.affiliation: Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012 (USA).|Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843-3003 (USA).
authors.forename: Robert V
authors.initials: RV
authors.lastname: Dennis
authors.affiliation: Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000 (USA).
authors.forename: Ye
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (USA).
authors.forename: Cherno
authors.initials: C
authors.lastname: Jaye
authors.affiliation: Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (USA).
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Fischer
authors.affiliation: Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000 (USA).
authors.forename: Uttam
authors.initials: U
authors.lastname: Singisetti
authors.affiliation: Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012 (USA).|Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843-3003 (USA).
authors.forename: Sarbajit
authors.initials: S
authors.lastname: Banerjee
keywords: NEXAFS; XPS; atomic layer deposition; graphene oxide; hafnium(IV) oxide