Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High-frequency rectification in graphene lateral p-n junctions   We observe a dc electric current in response to terahertz radiation in
lateral inter-digitated double-comb graphene p-n junctions. The junctions were
fabricated by selective ultraviolet irradiation inducing p-type doping in
intrinsic n-type epitaxial monolayer graphene. The photocurrent exhibits a
strong polarization dependence and is explained by electric rectification in
p-n junctions.

12
The categories of this paper are: nucl-th
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The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg