Effect of germane in gas phase on electronic properties of GeXSiY:H alloys deposited by RF plasma discharge

We have studied the effect of Ge-concentration in gas phase on electronic properties of GeXSiY:H alloys deposited by RF-PECVD. The relative gas phase Ge concentration was varied from [Ge]_gas= 50 % to 100 %. The electronic properties of the films were studied by the measurements of temperature dependence of dark conductivity σ_dark (T) in the range of T= 300 to 430 K. The temperature dependence curves were described by the thermal activated conduction model and activation energy and Fermi level parameters were calculated. A change in dark conductivity was found from 1.7×10^-6 Ω^-1cm^-1 at [Ge]_gas= 50 % to 1.1×10^-4 Ω^-1cm^-1 at [Ge]_gas =100 %. The correlation between Ge in gas phase and conductivity was reflected in activation energy and Fermi level values that varied from E_a= 0.37 to 0.23 eV and E_F=0.27 to 0.10 eV, respectively.