Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A two-colour heterojunction unipolar nanowire light-emitting diode by
  tunnel injection
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th