Based on subsequent gas-surface reactions, atomic layer deposition (ALD) allows the coating of flat surfaces as well as complex and high surface area nanostructures in a conformal and homogeneous manner with a precise control of the thickness of the deposited film at the angstroms scale. ALD is, therefore, specifically suited for the precise elaboration of nano-/hetero-structures.1,2 Alternative ALD processes have been developed by our group for fabricating functional materials based on boron nitride, metal oxide and carbon nanotubes.
Herein, two-step ALD process based on polymer derived ceramics route3 for BN thin films is first reported. In particular, functional quality crystalline BN nano/hetero-structures are fabricated using substrates or templates with different dimensionalities. Their applications as protective coatings as well as filter and absorber to purify polluted water from organic/oil are introduced.4
Maskless deposition of uniform and homogenous oxide thin films is also presented here with a lateral resolution tuned from millimeters to hundred micrometers range while keeping a film thickness in the range of a few to hundreds of nanometers with a control at the nanoscale.5 A modified open-air Spatial ALD head is indeed employed to fabricate complex multilayer oxide patterns on various substrates. This maskless ALD approach also enables controlled surface functionalization. In particular, local tuning of the wetting properties that permits controlling the water dropwise condensation is discussed.
Finally, vapour phase infiltration (VPI), an ALD derived technique, is introduced. Using a single precursor, isolated metallic entities are successfully installed in microporous porphyrin-based metal organic framework (MOF) by VPI.6 This technique is also implemented for filling single wall carbon nanotubes with chromophores. A particular attention is given to the controlled alteration of the optical properties of the starting materials as a function of the number of VPI cycles.