A method for producing nanostructures having a metal oxide shell, carried by a top face of a substrate whose greatest dimension is greater than or equal to 100 mm by MOCVD metalorganic chemical vapour deposition, including successive steps carried out in a reactor configured for MOCVD deposition of nucleation and growth. The nucleation step includes forming non-contiguous metal nuclei by depositing a metal by MOCVD using a metalorganic precursor on the top face of the substrate and oxidising the metal of the metal nuclei, to form oxidised nuclei and ensure stabilisation of the nuclei. The growth step includes depositing a metal by MOCVD using the metalorganic precursor, to form non-contiguous nanostructures by growth of the oxidised nanostructures, and oxidising the deposited metal of the nanostructures formed in the nucleation to form oxidised nanostructures.