The thickness dependence of the d.c. electrical conductivity and the variable range hopping in group IV amorphous elemental semiconductors

Abstract

Various aspects of variable range hopping conduction in amorphous semiconductors are discussed. It is argued that in those cases where the temperature dependence T of the d.c. electrical conductivity σ (T) as predicted by variable range hopping models is observed, the values obtained for α −1 (extend of the localised wavefunction) and N S (the density of localised carriers responsible for the transport) are in sharp disagreement with electron paramagnetic resonance. To reconcile this disagreement it is proposed that the cases with “good” behaviour (in accordance with variable range hopping models) might be in fact reflecting the inhomogeneous nature of the studied systems.