NOVELTY - The method comprises exposing a surface of a substrate comprising silicon-hydride groups to a vapor-phase initiator species under conditions, which facilitate a radical reaction between a portion of the silicon-hydride groups and the vapor-phase initiator species. The radical reaction comprises hydride extraction from the silicon-hydride groups for producing silicon radicals. The method further comprises sequentially exposing the silicon radicals to a vapor-phase monomer species under conditions.    USE - The method is useful for passivating a silicon substrate, which is useful in: a device such as a photovoltaic device, a solar cell, an organic light-emitting diode and a sensor device; and a chemical vapor deposition reactor (all claimed).    ADVANTAGE - The method is capable of easily and rapidly reducing surface recombination of minority carriers so that high quality electronic passivation is achieved and photovoltaic efficiency can be improved.    DETAILED DESCRIPTION - The method comprises exposing a surface of a substrate comprising silicon-hydride groups to a vapor-phase initiator species under conditions, which facilitate a radical reaction between a portion of the silicon-hydride groups and the vapor-phase initiator species. The radical reaction comprises hydride extraction from the silicon-hydride groups for producing silicon radicals. The method further comprises sequentially exposing the silicon radicals to a vapor-phase monomer species under conditions, which facilitate reaction between a portion of the silicon radicals and vapor-phase monomer species and polymerization of the monomer species for producing a polymer material covalently attached to the surface of the substrate. The vapor-phase initiator species includes an organic or organometallic species, terminal carbon-carbon double bond, and terminal carbon-carbon triple bond. The vapor-phase monomer species comprises a group capable of interacting with a chemical or biological analyte and a binding site for the chemical or biological analyte. The exposure of the substrate to the monomeric species is performed in the absence of a solvent at a temperature of less than or equal to 25 degrees C. The polymer material has a thickness of 800 nm to 1 micron, comprises a conducting polymer, an insulating polymer, and an anti- reflective coating, is formed at a temperature of less than or equal to 500 degrees C, and is covalently bonded to the surface of the substrate. The silicon radicals are capable of forming a bond with the monomer species. The initiator species and monomer species are both in vapor phase. INDEPENDENT CLAIMS are included for:    (1) a device comprising a silicon substrate; and    (2) a chemical vapor deposition reactor.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a passivation method.