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Selective Metal Oxide Nanoribbon Growth on Graphene Edges with Controllable Dimensions Using Atomic Layer Deposition. Kun Xu Phys 570x Research Proposal. Background. Graphene Edges. Background. Atomic Layer Deposition(ALD) on graphene. Goal.
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Selective Metal Oxide Nanoribbon Growth on Graphene Edges with Controllable Dimensions Using Atomic Layer Deposition Kun Xu Phys 570x Research Proposal
Background • Graphene Edges
Background • Atomic Layer Deposition(ALD) on graphene
Goal • Gain understanding of the reaction mechanics ?
Goal • Gain understanding of the reaction mechanics • Find the reaction window for different graphene edges using computational methods
Goal • Gain understanding of the reaction mechanics • Find the reaction window for different graphene edges using computational methods • Demonstrate the selectivity experimentally
Motivation • The underlying mechanism of ALD initial reaction at the interface is unclear • Potential applications • Oxides as termination for edge states • Oxide Nano-ribbon
Background • ALD process
Background • Advantage of ALD over CVD • Self-limiting reaction • Atomic level layer control • Extremely conformal and uniform in thickness
Background • ALD Precursors (for Al2O3) • TMA(Trimethylaluminium, Al2(CH3)6,)+ water • TMA + ozone
Background • Precursor Kinetics • TMA + water • TMA + ozone
Selected Literature Atomic-layer-deposited nanostructures for graphene-based nanoelectronics Appl. Phys. Lett. 92, 013101 (2008); DOI:10.1063/1.2828338 Conformal Al2O3 dielectric layer deposited by atomic layer deposition for graphene-based nanoelectronics Appl. Phys. Lett. 92, 203102 (2008); DOI:10.1063/1.2928228 Ozone-Based Atomic Layer Deposition of Alumina from TMA: Growth, Morphology, and Reaction Mechanism Chem. Mater., 2006, 18 (16), pp 3764–3773; DOI: 10.1021/cm0608903 Al2O3 as substrate
Methodology • Ab Initio study of initial reaction of precursors (calculate for the energetics of all reactant, products, intermediates, and transition states) • Gas phase (Gaussian) • Surface reaction (VASP) • Map the complete Potential energy surface(PES) • Rate constant calculation • Also the branching ratio
Methodology (continued) • Experimental verification • Perform ALD deposition under proposed conditions • Fine-tune the parameters • Characterization • AFM, SEM, XPS, etc.
Expected results • The theoretical results may differ from the actual experiment by orders of magnitude. • Still provide vital information for reaction mechanism
Resources needed • Computing time and software • Computer clusters • Software packages: • Gaussian, VASP, VTST, etc. • Prof. Francisco’s group here at Purdue • ALD reactor • Available in the Birck Center cleanroom • Time • Computation tasks can take a long time to complete depending on the system
Summary • Propose a computational chemistry approach to study and assist the design of ALD reaction on graphene edges • Motivations of the proposal • The steps needed to be taken to accomplished the proposed goals • The expected results • The resources needed Thank you!