The electrical and optical properties of hydrogenated amorphous
silicon-carbide alloy films (a-Si1-xCx:H), modified by
Fe+ ion implantation (D = 1×1016 -
1×1017 cm-2), have been investigated. Optical
transmission spectra have been measured in the visible range (400-900 nm)
and considerable absorption edge shift to the longer wavelength region has
been registered, together with well-defined decrease of transmittance in the
whole measured range. These effects are increased with the dose and are
similar for samples with different carbon content (x1=0.08 and
x2=0.15). Room temperature (RT) surface electrical
conductivity is also increased by Fe+ implantation and the effect
is most pronounced for the highest doses (D ~
1017cm-2). The temperature dependence of the
conductivity was measured in the temperature range from RT to 250
oC. The activation energy is considerably reduced and the
effect is again strongest for the highest doses. From the above results we
conclude that high doses Fe+ implantation in
a-Si1-xCx:H affects both the localised states deep
in the gap and the shallow states in the band tails.