화학공학소재연구정보센터
Thin Solid Films, Vol.564, 128-134, 2014
Oriented aluminum nanocrystals in a one-step process
Aluminum coatings were deposited on glass substrates by chemical vapor deposition using N-methylpiperidine (nmp) stabilized dichloroalane [Cl2AlH . 2nmp] as aluminum precursor. With regard to temperature, the experimental conditions were varied between 75 degrees C and 125 degrees C for the precursor and between 250 degrees C and 450 degrees C for the substrate. Depending on these parameters, highly textured layers could be deposited. The substrates have been consistently covered by a layer of idiomorphic, mostly distorted octahedra of aluminum single crystals. The morphologies of the structures and the degree of orientation of the crystals were investigated by a scanning electron microscopy and X-ray diffraction measurements. The high order of [111] orientation was found to decrease with increasing precursor and substrate temperature. We propose a mechanism for the generation of the octahedral structures based on the formation of mesocrystals. On heating, the dichloroalane (stabilized with nmp) loses the nmp ligands together with hydrogen and chlorine. The amine (nmp) seems to trigger the formation of aluminum crystals depending on the temperature and thus influences the texture of the Al-layer and the formation of well-formed octahedron-like structures. (C) 2014 Elsevier B.V. All rights reserved.