Valley polarization changes in chiral semiconductor nanocrystal/transition metal dichalcogenide heterostructures

Combining chiral nanomaterials with monolayer transition metal dichalcogenides (TMDs) can enhance valley polarization in TMDs to a level which can be optically detected at room temperature. Here we explore valley polarization enhanced via charge induced spin selectivity (CISS) by introduced chirality via ligand exchange in semiconductor nanocrystals, inorganic perovskite nanocrystals and CdSe quantum dots, both featuring optical bandgaps at around 2.48 eV. We combine these nanocrystals with a monolayer molybdenum disulfide to form heterostructures where semiconductor components interact via CISS charge transfer. We provide evidence for formation of charge states via ultrafast spectroscopy for both type of heterostructures which in turn provide evidence for possible selective population of the valleys of the monolayer TMD at room temperature.