Electron and Phonon Transport in SnSe 2D Nanoplatelets

Bulk single crystalline SnSe is a new promising thermoelectric material with a remarkably low thermal conductivity($\kappa )$ at above phase transition temperature (973K). Although the origin of the intrinsically low $\kappa $ of SnSe was previously attributed to strong anharmonicity in the chemical bonds, our recent work revealed that low density is another cause of the low $\kappa $ of the reported SnSe single crystals (Nature 539 (7627), E1-E2). Two-dimensional (2D) SnSe single crystalline nanoplatelets (NPs) provide an excellent platform to probe the true anharmonic effects in SnSe, which still remain elusive. A comprehensive array of tools such as EDX, EBSD and micro-Raman spectroscopy were used for characterizing 2D SnSe NPs grown using chemical vapor deposition. SnSe NPs with A1g, B3g, A2g and A3g vibrational modes identified by Raman spectroscopy grow along [100] direction. High-temperature thermopower and electrical conductivity will be presented.