Conductivity increase of amorphous Si and Ge by Mn

Amorphous Si and Ge are doped with Mn by co-sputtering. The electrical conductivity is incresed by as much as a factor of 10⁶～10⁷ in some cases by the addition of several at .% Mn. The temperature dependence of the conductivity shows the variable range hopping conduction for both samples with and without Mn. The results can be interpreted by the presence of two conduction processes; the variable range hopping through dangling bonds and that through Mn sites.