Journal Article electroluminescence 2D compounds 2D materials WSe2 amorphous carbon  chiroferromagnetic quantum dots chiroptical synapse circularly polarized light defects electrical confinement electronic applications epitaxy fluorination graphene hydrogenation light-emitting transistors light‐emitting transistor memristors multiple transitions nanomembrane neutral exciton patterned chemical functionalization thin films transition metal dichalcogenides ultraclean heterojunctions van der Waals heterostructure van der Waals heterostructures vertical heterostructure