Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Strain Engineering in Monolayer WS2 and WS2 Nanocomposites   There has been a massive growth in the study of transition metal
dichalcogenides (TMDs) over the past decade, based upon their interesting and
unusual electronic, optical and mechanical properties, such as tuneable and
strain-dependent bandgaps. Tungsten disulfide (WS2), as a typical example of
TMDs, has considerable potential in applications such as strain engineered
devices and the next generation multifunctional polymer nanocomposites.
However, controlling the strain, or more practically, monitoring the strain in
WS2 and the associated micromechanics have not been so well studied. Both
photoluminescence spectroscopy (PL) and Raman spectroscopy have been proved to
be effective but PL cannot be employed to characterise multilayer TMDs while it
is difficult for Raman spectroscopy to reveal the band structure. In this
present study, photoluminescence and Raman spectroscopy have been combined to
monitor the strain distribution and stress transfer of monolayer WS2 on a
flexible polymer substrate and in polymer nanocomposites. It is demonstrated
that WS2 still follows continuum mechanics on the microscale and that strain
generates a non-uniform bandgap distribution even in a single WS2 flake through
a simple strain engineering. It is shown that these flakes could be useful in
optoelectonic applications as they become micron-sized PL emitters with a band
gap that can be tuned by the application of external strain to the substrate.
The analysis of strain distributions using Raman spectroscopy is further
extended to thin-film few-layer WS2 polymer nanocomposites where it is
demonstrated that the stress can be transferred effectively to WS2 flakes. The
relationship between the mechanical behaviour of single monolayer WS2 flakes
and that of few-layer flakes in bulk composites is investigated.

7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga