Electrical Properties of Hydrogenated Amorphous Si$\text{}_{1-x}$Ge$\text{}_{x}$ Thin Films

Thin films of hydrogenated amorphous Si-Ge alloys were obtained by r.f. sputtering in Ar + H$\text{}_{2}$ gas atmosphere using composite targets of Si and Ge. Dark conductivity and photoconductivity were measured in the temperature range of 300-500 K for films with x varying from 0.11 to 0.63. Both dark conductivity and photoconductivity exibit activation type dependences in the temperature range studied. Heterogeneity two-phase model and a model based on Fermi level shift with temperature were invoked to discuss the conduction mechanism.