  The transient high-frequency noise response of two-dimensional MoS2 under
abrupt large signal switching field conditions is studied by means of an
ensemble Monte Carlo simulator. Low-to-high and high-to-low transitions are
analyzed at low (77 K) and room temperature, considering several underlying
substrates. The incorporation of stochastic individual scattering events allows
capturing the transient collective phonon-electron coupling, which is shown to
be responsible for the appearance of an oscillatory behaviour in the average
velocity and energy at low temperature in the case of MoS2 on SiO2, hBN and
Al2O3. Activation and deactivation of surface polar phonon emissions in the
low-to-high field switching process yield to the appearance of a relevant peak
in the power spectral density of velocity fluctuations in the THz range. The
results show the important influence of the substrate type in the noise
behaviour of MoS2 at very high frequencies, which is critical for the design of
future FET devices based on 2D TMD technology.
