An epitaxial film grows in a crystallographic relationship with the substrate. For instance, a single crystal substrate will yield a single crystal film. Epitaxial films are typically deposited using a vapor phase (Physical and Chemical) or using a liquid phase, (metallorganic decomposition). In this approach, the film nucleates at the substrates and grows epitaxially. Depending on the deposition technique, the substrate temperature, the film growth rate determines whether the film grows epitaxially or in the form of a randomly oriented poly-crystalline structure.

A novel method was developed that relies on synthesis of unagglomerated nanoparticles that are colloidally dispersed in liquid. This is used to prepare a well packed coating or thin film using colloidal deposition techniques, such as dip coating, spin coating, flow coating, spray coating or inkjet.

Heat treatment of the film allows crystallization and epitaxial growth on the substrate.

Various approaches have been found useful in producing dispersions of amorphous nanoparticles. The nanoparticle surfaces can be passivated with a dispersing agent. The concept described has been demonstrated for fabrication of textured and epitaxial YBa₂Cu₃O_x high temperature superconductor thin films. The process involves preparation of a colloidal dispersion of YBa₂Cu₃O_x and deposition of thin films onto a single crystal or textured substrate. A patent application exists.

Also shown is an XRD of the YBCO film which shows that the film is c-axis oriented in epitaxy with the LaAlO₃ single crystal substrate onto which it was deposited. Some a and b axis oriented grains were also observed which are expected to be removed by optimization of the heat treatment condition. The microstructure of the film is also shown and the film was found to be dense and primarily c-axis oriented. A critical current density of ~2x10⁶A/cm² at 77K and self field was observed in YBa₂Cu₃O_x films produced using this technique.

Results are comparable to those achieved on conventional films produced by pulsed laser ablation (PLD) or Trifluroacetate (TFA) based metallorganic decomposition process (MOD).

Nascent Technology includes a deposition process that does not involve any vacuum and can be easily scaled into an industrial process. It can be extended to a wide range of materials which includes but not limited to YSZ, (La,Sr)MnO₃, BaTiO₃, CeO₂, PZT, etc. Coatings can be applied to single crystal or textured substrates (including metallic substrates)