Mixed Dimensionality van der Waals heterostructure : nano-graphene @ 2D materials – MIDI

The project MIDI aims at studying van der Waals heterostructures made of nanographenes stacked on or in-between 2D materials (h-BN, Transition metal dichalcogenides) that provide atomically clean interfaces to enhance the optical properties of the nano-carbons in view of quantum light emission. The project targets both the enhancement of coherence properties of single emitters embedded in large bandgap materials (hBN) or the creation of new excited states like interlayer excitons in case of a type II band alignment scheme with 2D semi-conducting encapsulants (TMDCs). The originality of MIDI with respect to the widely studied 2D hetero-structures lies in the additional knob provided by the tunable lateral quantum confinement in the bottom-up grown nano-carbons. MIDI is based on solid preliminary results both in our teams and in the literature. MIDI aims to push forward the bottom up synthesis of nanographene by organic chemistry, allowing a atomically precise control of the structures. Evaporation and spin coating approaches will be investigated to fabricate van der Waals stacks containing the nanographene either deposited at the surface or embeded in the stack. Electronic properties will be invetigated by near field spectroscopy in a cryogenic scanning tunneling microscope to inspect the electro/photo-luminescence with sub-nm resolution. The third objective of MIDI is to probe and improve the optical properties of the mixed dimensionnality heterostructure using cryogenic micro-photoluminescence techniques at the single nano-object level, with emphasis on the signatures of improved quantum coherence, many body effects and collective effects when several excitations are created in the same nano-graphene.