Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Suspension and simple optical characterization of two-dimensional
  membranes   We report on a method for suspending two-dimensional crystal materials in an
electronic circuit using an only photoresists and solvents. Graphene and
NbSe${}_2$ are suspended tens of nanometers above metal electrodes with
clamping diameters of several microns. The optical cavity formed from the
membrane/air/metal structures enables a quick method to measure the number of
layers and the gap separation using comparisons between the expected colour and
optical microscope images. This characterization technique can be used with
just an illuminated microscope with a digital camera which makes it adaptable
to environments where other means of characterization are not possible, such as
inside nitrogen glove boxes used in handling oxygen-sensitive materials.

17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat