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Title: Graphene Layer Growth Chemistry: Five-Six-Ring Flip Reaction

Abstract

A theoretical study revealed a new reaction pathway, in which a fused five and six-membered ring complex on the zigzag edge of a graphene layer isomerizes to reverse its orientation, or 'flips,' after activation by a gaseous hydrogen atom. The process is initiated by hydrogen addition to or abstraction from the surface complex. The elementary steps of the migration pathway were analyzed using density-functional theory (DFT) calculations to examine the region of the potential energy surface associated with the pathway. The DFT calculations were performed on substrates modeled by the zigzag edges of tetracene and pentacene. Rate constants for the flip reaction were obtained by the solution of energy master equation utilizing the DFT energies, frequencies, and geometries. The results indicate that this reaction pathway is competitive with other pathways important to the edge evolution of aromatic species in high temperature environments.

Authors:
; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE. Office of the Chief Financial Officer. Other Costsand Credits
OSTI Identifier:
918666
Report Number(s):
LBNL-62179
R&D Project: 19900; TRN: US200819%%390
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Conference
Resource Relation:
Conference: 5th US Combustion Meeting Organized by theWestern States Section of the Combustion Institute and Hosted by theUniversity of California at San Diego, San Diego, CA, March 25-28,2007
Country of Publication:
United States
Language:
English
Subject:
37; AROMATICS; CALIFORNIA; CHEMISTRY; COMBUSTION; HYDROGEN; HYDROGEN ADDITIONS; ORIENTATION; PENTACENE; POTENTIAL ENERGY; SUBSTRATES; TETRACENE

Citation Formats

Whitesides, Russell, Domin, Dominik, Lester Jr., William A., and Frenklach, Michael. Graphene Layer Growth Chemistry: Five-Six-Ring Flip Reaction. United States: N. p., 2007. Web.
Whitesides, Russell, Domin, Dominik, Lester Jr., William A., & Frenklach, Michael. Graphene Layer Growth Chemistry: Five-Six-Ring Flip Reaction. United States.
Whitesides, Russell, Domin, Dominik, Lester Jr., William A., and Frenklach, Michael. Sat . "Graphene Layer Growth Chemistry: Five-Six-Ring Flip Reaction". United States. doi:. https://www.osti.gov/servlets/purl/918666.
@article{osti_918666,
title = {Graphene Layer Growth Chemistry: Five-Six-Ring Flip Reaction},
author = {Whitesides, Russell and Domin, Dominik and Lester Jr., William A. and Frenklach, Michael},
abstractNote = {A theoretical study revealed a new reaction pathway, in which a fused five and six-membered ring complex on the zigzag edge of a graphene layer isomerizes to reverse its orientation, or 'flips,' after activation by a gaseous hydrogen atom. The process is initiated by hydrogen addition to or abstraction from the surface complex. The elementary steps of the migration pathway were analyzed using density-functional theory (DFT) calculations to examine the region of the potential energy surface associated with the pathway. The DFT calculations were performed on substrates modeled by the zigzag edges of tetracene and pentacene. Rate constants for the flip reaction were obtained by the solution of energy master equation utilizing the DFT energies, frequencies, and geometries. The results indicate that this reaction pathway is competitive with other pathways important to the edge evolution of aromatic species in high temperature environments.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Mar 24 00:00:00 EDT 2007},
month = {Sat Mar 24 00:00:00 EDT 2007}
}

Conference:
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  • Reaction pathways are presented for hydrogen-mediated isomerization of a five and six member carbon ring complex on the zigzag edge of a graphene layer. A new reaction sequence that reverses orientation of the ring complex, or 'flips' it, was identified. Competition between the flip reaction and 'ring separation' was examined. Ring separation is the reverse of the five and six member ring complex formation reaction, previously reported as 'ring collision'. The elementary steps of the pathways were analyzed using density-functional theory (DFT). Rate coefficients were obtained by solution of the energy master equation and classical transition state theory utilizing themore » DFT energies, frequencies, and geometries. The results indicate that the flip reaction pathway dominates the separation reaction and should be competitive with other pathways important to the graphene zigzag edge growth in high temperature environments.« less
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  • Higher performance is the main driver in the integrated circuit (IC) market, but along with added function comes the cost of increased input/output connections and larger die sizes. Space saving approaches aimed at solving these challenges includes two technologies; 3D stacking (3D-ICs) and flip chip assemblies. Emerging ICs require sub-micron scale interconnects which include vias for 3D-ICs and bump bonds for flip chips. Photolithographic techniques are commonly used to prepare templates followed by metal vapor deposition to create flip chip bump bonds. Both the lithography step and the metal properties required for bump bonding contribute to limiting this approach tomore » a minimum bump size of -10 ?m. Here, we present a wet chemistry approach to fabricating uniform bump bonds of tunable size and height down to the nanoscale. Nanosphere lithography (NSL), a soft lithographic technique, is used to create a bump bond template or mask for nanoscale bumps. Electrochemical deposition is also used through photoresist templates to create uniform bump bonds across large area wafers or dies. This template approach affords bumps with tunable diameters from 100s of nanometers to microns (allowing for tunable interconnect pitch and via diameters) while the use of constant current electroplating gives uniform bump height over large areas (>1 cm{sup 2}).« less
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