@starwarrior stated "Unlike Au wire Si reacts to O2. Si is actually a better conductor than Au however it reacts when it is exposed to O2."
This statement is incorrect, in addition to referring to silver as Si instead of its correct symbol Ag as @jeffbij pointed out previously. Pure silver (Ag) will not readily form silver oxide (Ag2O) under ambient conditions. Under ambient conditions some physisorbed oxygen is typically observed on silver. For dissociative chemisorption of the oxygen to occur requires heating the silver to several hundred degrees C after which Ag2O is observed.
I would like to clarify that silver in it bulk form is not readily reactive with O2 but in its atomic form it is very reactive. For example in silver nanoparticles, a large portion of the silver atoms at the surface of the nanoparticle are not fully coordinated (have atomic-like properties) and are very reactive. This is the reason that silver nanoparticles are widely used as catalysts. It is possible that a poor silver film with a lot of defects at the surface could have silver atoms that are not fully coordinated and could react with O2 under ambient conditions at these defect sites