One dimensional Van der Waals HETEROstructures – HeteroBN-C

The proposal HETEROBN-C aims at the controlled synthesis of freestanding one dimensional (1D) hexagonal Boron Nitride (hBN)/Carbon nanotube (CNTs) van der Waals (VdW) heterostructures and at the investigation of their structural and optical properties. In line with the spectacular improvement and emergence of new physical properties in 2D VdW heterostructures, the curvature and confinement effects provided by the reduced dimensionality of 1D VdW heterostructures make them highly attractive. These new 1D materials are of particular interest for applications ranging from sensing and quantum optics, to biological labeling. The project will focus on the understanding of the controlled growth of hBN by atomic layer deposition (ALD) onto/into suspended single wall CNTs as well as on the investigation of the relationship between the structure and the optical properties (excitonic luminescence yield, spectral properties,...). Particular attention will be paid at developing highly-controlled method of hBN deposition inside and outside CNTs, studying the growth mechanism and the resulting interaction at the nanoscale. In this regard, single-wall carbon nanotubes (SWCNTs), used as support, will be coated with a thin (from a few nm down to one monolayer) hBN layer using ALD. By means of advanced analytic transmission electron microscopy combined with DFT calculation, the relationship between the deposited hBN and the graphitized carbon support will be deeply investigated as the function of the fabrication parameters. Understanding of the BN growth on the inner and outer part of the SWCNT wall is indeed the key for a fine tuning of VdW heterostructure interfaces. On the optical side, the interface features (inter-tube spacing, orientational correlation…), expected to strongly influence the VdW coupling and thus the electronic and optical properties of this 1D heterostructure, will be studied both (1) in the near-IR spectral domain of the CNT optical response in the prospect of reaching the intrinsic limit (truly one-dimensional radiative-limited excitonic emission) of the CNT properties thanks to the hBN-encapsulation, and (2) in the deep-UV spectral domain of the BN optical response for observing the luminescence of BN layer deposited in the inner CNT wall.