Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct imaging of dopant and impurity distributions in 2D MoS$_2$   Molybdenum disulfide (MoS$_2$) nanosheet is a two-dimensional material with
high electron mobility and with high potential for applications in catalysis
and electronics. We synthesized MoS$_2$ nanosheets using a one-pot wet-chemical
synthesis route with and without Re-doping. Atom probe tomography revealed that
3.8 at.% Re is homogeneously distributed within the Re-doped sheets. Other
impurities are found also integrated within the material: light elements
including C, N, O, and Na, locally enriched up to 0.1 at.%, as well as heavy
elements such as V and W. Analysis of the non-doped sample reveals that the W
and V likely originate from the Mo precursor.

3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin