Intrinsic and Strain-Dependent Properties of Suspended WSe Crystallites toward Next-Generation Nanoelectronics and Quantum-Enabled Sensors.

Two-dimensional (2D) layered materials exhibit great potential for high-performance electronics, where knowledge of their thermal and phononic properties is critical toward understanding heat dissipation mechanisms, considered to be a major bottleneck for current generation nanoelectronic, optoelectronic, and quantum-scale devices. In this work, noncontact Raman spectroscopy was used to analyze thermal properties of suspended 2D WSe membranes to access the intrinsic properties. Here, the influence of electron-phonon interactions within the parent crystalline WSe membranes was deciphered through a comparative analysis of substrate-supported WSe, where heat dissipation mechanisms are intimately tied to the underlying substrate.

Light-matter interactions in two-dimensional layered WSe for gauging evolution of phonon dynamics.

Phonon dynamics is explored in mechanically exfoliated two-dimensional WSe using temperature-dependent and laser-power-dependent Raman and photoluminescence (PL) spectroscopy. From this analysis, phonon lifetime in the Raman active modes and phonon concentration, as correlated to the energy parameter , were calculated as a function of the laser power, , and substrate temperature, . For monolayer WSe, from the power dependence it was determined that the phonon lifetime for the in-plane vibrational mode was twice that of the out-of-plane vibrational mode for in the range from 0.