A new procedure for calculating the density and energy distribution of localized hopping sites in disordered semiconductors, using low-temperature electrical conductivity data

Quantum mechanical tunneling between localized sites will dominate carrier transport in disordered solids, at sufficiently low temperatures, predicated by the localized state concentration and energy distribution. We previously advanced a simple procedure for interpreting carrier mobility data, for an energy-independent density of states (DOS). Here, we show that it can easily be extended to interpret electrical conductivity data, for both energy-independent and energy-dependent DOS distributions. We also show that the concept of transport energy is of considerable value in understanding the factors that underlie the experimental behavior. Furthermore, the new procedure yields credible and entirely self-consistent results when applied to published conductivity data. Finally, we contrast its success with the major inconsistencies that arise when results obtained using the Mott 'T-1/4' model are examined in more than superficial detail.