Creation of Nanoporous Thin-Film Composites via Ion Beam Assisted Deposition

摘要

The main regularities of formation of V-N-He thin films deposited under conditions of bombardment with mixed beams of nitrogen and helium ions are studied; their structural phase, electrophysical, and adsorption characteristics are explored. The electron microscopy data confirms that the formation of the structure of V-N-He compounds occurs under conditions of competition of several simultaneous processes which lead to the formation of a nanocrystalline structure with the diameter of micropores from 5 nm to 5 urn. The role of ion bombardment and gas adsorption from the residual atmosphere in the formation of porosity is considered. The comparison of data of Rutherford backscattering (RBS) and profilometry allowed the determination of the value of film porosity-27%. In the range of explored hydrogen pressures (to 0.35 MPa), up to 7 wt % H was adsorbed. It is shown that the main part of hydrogen is accumulated in pores. The amount of adsorbed gas is determined by the size of pores, their distribution, and composition of the gas medium in them.