NOVELTY - Preparing (M1) a deposition on a substrate involves providing an anode comprising electrolytically ionisable material and cathode both in electrical contact with electrically conductive liquid, optionally comprising anions capable of forming a molecule with the electrolytically ionised material; electrolytically oxidising the ionisable material under formation of cations that dissolve in the liquid; evaporating the cations or molecules of cations and the anions from the liquid; and depositing the cations or the molecules on the substrate.    USE - For preparing a deposition on a substrate i.e. silicon-based substrates or metallic substrates (preferably Si, SiO2, stainless steel, and Al), ceramic substrates, glass or glass substrates and polymer substrates; and for manufacturing an electronic or optoelectronic device (claimed). Also useful in the semiconductor industry, glass industry and for making hard coatings such as Al2O3 coatings from AlCl3 solid precursors, coatings on glass for solar cell applications, anti-reflection coatings, low-emissive coatings, hard coatings on tools for increased durability and lifetime, low- epsilon coatings, and metallization coatings; and in tools, glass windows, photovoltaics, light emitting diodes such as organic light emitting diodes and integrated circuits.    ADVANTAGE - The method provides an efficient precursor delivery system that can deliver a large vapor flow of precursor material to vapor deposition processes, where the vapor flow is stable in its composition and flux. The improved vapor deposition method solves the problems encountered with in conventional vapor deposition techniques by providing a vapor deposition method that can be accurately and preferably easily controlled and it does not require the use of a carrier gas. Accordingly, subliming the precursor material from an ionic liquid costs less energy than conventional sublimation processes. After the vaporization process it is possible to regenerate the ionic liquid. Depending on the type and morphology of the impurities, remaining impurities can be separated from the ionic liquid by means of separation technologies and the ionic liquid can then be reused. Moreover, since the ionic liquid is not readily vaporized, the loss of ionic liquid is extremely low. Hence, there is no, or hardly any, consumption of the ionic liquid during the process. The method provides high purity of the synthesized precursor without the need for separate purification steps. In method, the electrode that easy to handle, and the electrode can readily controls by adjusting the electrical current or voltage of electrode.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for apparatus for evaporating a compound comprising a container for holding an electrically conductive liquid, which container containing an ion selective membrane dividing container in a first compartment having a cathode and a second compartment having an anode, where anode comprises electrolytically ionisable material; a conduit for allowing electrically conductive liquid comprising electrolytically ionised material from anode to be transported from second compartment to a film evaporator; and a conduit for allowing electrically conductive liquid to be transported from film evaporator to second compartment.