Electrical conductivity in amorphous Si(O or H)-Au films

SiO films obtained by sputtering in an ArO mixture with an oxygen partial pressure less than 3% are similar to a-Si films: the resistivity is proportional to exp (T₀/T)^{$\text{1}\text{4}$} and T₀ increases with oxygen content and decreases with increasing Au concentration (? 3.7 at.%). On the other hand, above an oxygen partial pressure of 5% one obtains insulating amorphous SiO₂ films. Conductivity appears in such films for Au? 13 at.% (? the percolation threshold) and then the resistivity is proportional to exp (T₀/T)^{$\text{1}\text{2}$}. The same behavior is observed when oxygen is replaced by hydrogen.