Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Multilayer C2N: Effect of Stacking Order and Number of Layers on Bandgap
  and Its Controlled Electronic Properties by External Electric Field   Successful synthesis of the nitrogenated holey two-dimensional structures C2N
(Nat. Commun. 2015, 6, 1-7) using simply wet-chemical reaction offer a
cost-effective way to generate other 2D materials with novel optical and
electronic properties. Using the few-layer C2N as models, we have performed an
ab initio study of electronic properties of layered C2N. Band gaps of this
system exhibit monotone decreasing as the number of layers increase. And a
direct-gap to indirect-gap transition at the bulk C2N. Besides, when we apply
an out-of-plane electric field on few-layer C2N, the band gap of multilayer C2N
will be decreased as the electric field increased and a semiconductor-semimetal
transition will happen for five-layer C2N under an appropriate electric field,
whereas the band gap of monolayer C2N is unchanged under electric field. Owing
to their tunable bandgaps in a wide range, layers C2N will have tremendous
opportunities to be applied in nanoscale electronic and optoelectronic devices.

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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: atom-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: plasm-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-th
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The categories of this paper are: stat
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The categories of this paper are: nlin
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-bio