Development and Applications of ReaxFF Reactive Force
Fields for Group-III Gas-Phase Precursors and Surface Reactions with
Graphene in Metal–Organic Chemical Vapor Deposition Synthesis
posted on 2021-05-06, 11:03authored bySiavash Rajabpour, Qian Mao, Nadire Nayir, Joshua A. Robinson, Adri C. T. van Duin
Two-dimensional (2D) materials exhibit
a wide range of optical,
electronic, and quantum properties divergent from their bulk counterparts.
To realize scalable 2D materials, metal–organic chemical vapor
deposition (MOCVD) is often used. Here, we report two ReaxFF reactive
force fields, GaCH-2020 and InCH-2020, which were developed to investigate
the MOCVD gas-phase reactions of Ga and In film growth from trimethylgallium
(TMGa) and trimethylindium (TMIn) precursors, respectively, and the
surface interactions of TMGa and TMIn with graphene. The newly developed
force fields were applied to determine the optimal conditions for
the thermal decomposition of TMGa/TMIn to achieve Ga/In nanoclusters
with low impurities. Additionally, the cluster formation of Ga/In
on a graphene substrate with different vacancies and edges was studied.
It was found that a graphene with Ga-functionalized monovacancies
could help conduct directional Ga cluster growth via covalent bonds.
Moreover, under specific growth conditions, we found that Ga atoms
growing on armchair-edged graphene not only exhibited a superior growth
ratio to In atoms but also produced a widely spread 2D thin layer
between graphene edges.