Distinguishing Optical and Acoustic Phonon Temperatures and Their Energy Coupling Factor under Photon Excitation in nm 2D Materials.

ABSTRACT: Under photon excitation, 2D materials experience cascading energy transfer from electrons to optical phonons (OPs) and acoustic phonons (APs). Despite few modeling works, it remains a long-history open problem to distinguish the OP and AP temperatures, not to mention characterizing their energy coupling factor (G). Here, the temperatures of longitudinal/transverse optical (LO/TO) phonons, flexural optical (ZO) phonons, and APs are distinguished by constructing steady and nanosecond (ns) interphonon branch energy transport states and simultaneously probing them using nanosecond energy transport state-resolved Raman spectroscopy. ΔT _{OP -AP} is measured to take more than 30% of the Raman-probed temperature rise. A breakthrough is made on measuring the intrinsic in-plan

SUBMITTER: Wang R 

PROVIDER: S-EPMC7341092 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature