Microwave irradiation offers a simple and scalable route to tailor the phonon dynamics and electronic response of two-dimensional materials. This work explores how such irradiation modifies Fano asymmetric resonance and vibrational Raman spectra in 2 H-MoS2 nanoflakes synthesized by the hydrothermal method. Raman spectra recorded over 10–40 min of microwave irradiation reveal distinct vibrational frequency shifts: the in-plane \(\:{E}_{2g}^{1}\) mode redshifts from 380 to 376 cm-1, while the out-of-plane \(\:{A}_{1g}\) mode shifts from 405 to 402 cm-1. The Fano resonance asymmetry strength also decreases with irradiation, as the strength of the in-plane mode reduces from 0.19 to 0.11 and the out-of-plane mode from 0.05 to 0.04 (1/|q|), confirming the strong sensitivity of asymmetric strength to microwave fields. Microwave irradiation, defect activation, and strain are the external perturbations found to drive these changes, which in turn modulate the electron–phonon coupling and alter the vibrational response. Complementary UV–Vis absorbance measurements support these findings by showing band gap narrowing and excitonic shifts with increasing irradiation time. Together, the results demonstrate that microwave irradiation serves as a controllable external stimulus to tune the vibrational and electronic properties of MoS2. This study clarifies the link between Fano resonance, phonon dynamics, and external perturbations, providing a pathway for the defect engineering of transition metal dichalcogenides in quantum technologies, optoelectronics, and nanoelectronics.
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