Barrier coatings

A method for depositing a barrier coating, comprising the steps of:

• providing at least one surface for deposition;
• depositing reaction or recombination products of reacting species on the surface;
• changing the compositions of the reactants fed into the reactor chamber during the deposition to form a compositionally organic-inorganic coating;
• said coating comprising at least one substantially organic zone and at least one substantially inorganic zone;
• performing refractive index modification of the at least one inorganic zone by varying the precursor gas composition, said refractive index of the inorganic zone being adjusted to provide a substantially uniform refractive index along an axis of light transmission through said barrier coating.

A method comprising:

• providing a device disposed on a substrate;
• and
• coating a surface of said device with a barrier coating of organic-inorganic composition, the barrier coating having optical properties that are substantially uniform along an axis of light transmission, said axis oriented substantially perpendicular to the surface of the coating,
• wherein the barrier coating comprises at least one zone substantially organic in composition and at least one zone substantially inorganic in composition.