> Hello all,
>
> I'm currently working on a gas sensor using  Au electrodes. The electrodes
> has a 1 um gap with ~0.5 um thick of SiO2 layer underneath. Without adding
> any semiconductor layers on top of the electrodes, I've got the R reading
> changed relevant to the presence or absence of testing gases, methanol for
> example.
>
> I don't know how this could happen.I wonder if anyone has the same
> experience that can share your idea to me. Any responses would be greatly
> appreciated.
>
> Terry

Hi, how high is the potential at which You are measuring?

if You exceed 1,5V You will get probably some current due to the
oxidation/reduction of Your electrodes.
Also check possible electrochemical reactions which You may provoke with
this potential.

Greets Jan