Investigating the phonon line shapes of TMDs: An analytical approach

Several phenomena can affect the phonon bands of low-dimensional systems, and their proper assignment and interpretation are essential in elucidating their effect on electronic, optical, and optoelectronic properties. Using an analytical approach, we investigate the similarities and differences of the layered effect, the phonon confinement effect, the Breit–Wigner–Fano effect, the inhomogeneous heating effect, and disorder-induced effects in the phonon line shapes of WS₂ and MoS₂. The subtle differences and similarities are critical in making proper assignments and interpretations of the phonon line shapes and are useful as guidance in the behavior of phonon bands, particularly in TMDs, and more generally in low-dimensional systems.