Abstract
Two-dimensional materials exhibit great potential for high-performance
electronics applications and the knowledge of their thermal properties
is extremely necessary, since they are closely related to efficient heat
dissipation and electron-phonon interactions. In this study we report
the temperature-dependence of the out-of-plane A(1g) Raman mode of
suspended and supported CVD-grown single-crystalline tungsten diselenide
(WSe2) monolayer. The A(1g) phonon wavenumber is linearly red-shifted
for temperature ranging from 98 to 513 K, with first-order temperature
coefficients beta of -0.0044 and -0.0064 cm(-1)/K for suspended and
supported monolayer WSe2, respectively. The higher beta module value for
supported sample is attributed to the increase of the phonon
anharmonicity due to the phonon scattering with the surface roughness of
the substrate. Our analysis of the temperature-dependent phonon dynamics
reveal the influence of the substrate on thermal properties of monolayer
WSe2 and provide fundamental information for developing of
atomically-thin 2D materials devices. (C) 2019 Author(s).
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