NOVELTY - Formation of electronic article (A1) comprising optoelectronic semiconductor with dielectric layer; and gradient refractive index coating which is sandwiched between optoelectronic semiconductor and dielectric layer, and comprising gradient of carbide and oxycarbide, where method involves continuously depositing gradient refractive index coating on optoelectronic semiconductor using plasma-enhanced chemical vapor deposition (46) in dual frequency configuration; and disposing dielectric layer on gradient refractive index coating to form electronic article.    USE - For manufacturing electronic article e.g. photovoltaic (solar) cell and light emitting diodes (LEDs) (claimed), used in optoelectronic semiconductors.    ADVANTAGE - The method provides increased conversion efficiency, reduced light reflection and light absorption of electronic articles. The continuous deposition of gradient refractive index coating forms the gradient of carbide and oxycarbide and minimizes number of optical interfaces in electronic article, this reduces reflection and provides electronic article with increased functionality. The gradient also reduces both reflection and absorption of light, thus allowing greater amounts of light to reach or leave the optoelectronic device, thus increasing the efficiency of electronic article.    DETAILED DESCRIPTION - Formation of electronic article (A1) comprising comprising optoelectronic semiconductor with refractive index of 3.7 plus minus 2; dielectric layer with thickness 50 mu m and refractive index of 1.4 plus minus 0.1; and gradient refractive index coating which is sandwiched between optoelectronic semiconductor and dielectric layer, having thickness of 50-400 nm, and refractive index along thickness of 2.7 plus minus 0.7 at first end to 1.5 plus minus 0.1 at second end adjacent to dielectric layer, and comprising gradient of carbide and oxycarbide, each comprises silicon and germanium atom, where method involves continuously depositing gradient refractive index coating on optoelectronic semiconductor using plasma-enhanced chemical vapor deposition (PECVD) (46) in dual frequency configuration; and disposing dielectric layer on gradient refractive index coating to form electronic article. An INDEPENDENT CLAIM is included for photovoltaic cell module comprising photovoltaic cell having refractive index of 3.7 plus minus 2; dielectric layer disposed on photovoltaic cell and having thickness 50 mu m and refractive index of 1.4 plus minus 0.1; and gradient refractive index coating comprising gradient of hydrogenated silicon carbide and hydrogenated silicon oxycarbide.    DESCRIPTION OF DRAWING(S) - The figure shows schematic diagram of plasma enhanced chemical vapor deposition (PECVD) apparatus.    Plasma enhanced chemical vapor deposition (PECVD) system (46)    First electrode (48)    Second electrode (50)    Third electrode (52)    Plasma (54)    Electrode reactor (56)