N-type conductivity of nanostructured thin film composed of antimony-doped Si nanocrystals in silicon nitride matrix

Highly conductive thin films composed of antimony-doped Si nanocrystals (Si-NCs) embedded in the Si₃N₄ matrix were prepared by co-sputtering technique. The N-type electrical behavior in the doped films as observed from Hall measurements was attributed to free carriers generation resulting from the effective Sb doping. Quantitative analysis has demonstrated that effective Sb doping at a concentration of 0.54 at.% results in an improvement on the electrical conductivity (σ) by more than six orders of magnitude, up to 2.8×10⁻² S/cm. The charge transport mechanism can be explained well by the percolation-hopping model where the conductivity follows σ~exp[−(T₀/T)]^1/2 at temperature lower than 220 K.