Luminescence and optical second harmonic generation in atomically thin layered transition metal dichalcogenides

Abstract

This work concerns the photoluminescence (PL) properties of 2H-WS2, 2H-WSe2, 2H- and 3R-MoS2 bulk crystals and 2D flakes intercalated with halogen molecules, caused by direct gap emission with both neutral and charged exciton recombination, as well as by bound excitons recombination. The crystals were grown through the chemical-vapor method, using iodine, bromine or chlorine as transport agents. Single- and few-layer flakes of TX2 samples have been obtained by mechanical exfoliation of bulk crystals.