Ab initioestimate of temperature dependence of electrical conductivity in a model amorphous material: Hydrogenated amorphous silicon

Abstract

We present an ab initio calculation of the DC conductivity of amorphous silicon and hydrogenated amorphous silicon. The Kubo-Greenwood formula is used to obtain the DC conductivity, by thermal averaging over extended dynamical simulation. Its application to disordered solids is discussed. The conductivity is computed for a wide range of temperatures and doping is explored in a naive way by shifting the Fermi level. We observed the Meyer-Neldel rule for the electrical conductivity with EMNR=0.06 eV and a temperature coefficient of resistance close to experiment for a-Si:H. In general, experimental trends are reproduced by these calculations, and this suggests the possible utility of the approach for modeling carrier transport in other disordered systems.

Network structure and dynamics of hydrogenated amorphous silicon

“…This linearity is revealed in Figure 4. The implications to transport are discussed elsewhere [38]. 7 Staebler-Wronski effect…”

Structure-property relations in amorphous carbon for photovoltaics

“…To compute the mobility edges in a-C and a-C:H, we quantified the localization of the KS orbitals by evaluating their inverse participation ratios (IPR) following the procedure in Ref. 26. We observed sharp transitions in the IPR values for increasing energies both in the valence and conduction bands, thus allowing us to identify the mobility edges as the energies of the IPR value transition, and consequently compute the mobility gaps.…”

Computer simulations of glasses: the potential energy landscape

“…There is also a strong correlation between the degree of electronic localisation and the sensitivity of the electrons to lattice vibrations, i.e. strong localisation is associated with a larger electron-phonon coupling, as has been demonstrated for hydrogenated amorphous silicon [242,243].…”