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Computer simulation studies of low-temperature hopping in spatially and energetically disordered systems

J. M. MARSHALL1,*

Affiliation

  1. School of Engineering, University of Wales Swansea, 64 Ridgeway, Killay, Swansea SA2 7AP, U.K.

Abstract

Quantum mechanical tunnelling between localised sites can dominate carrier transport in sufficiently disordered solids. We examine such transport, employing a Monte Carlo simulation technique. Initially, the advantages and drawbacks of this approach are indicated. The discrepancies between the mobility and the diffusion coefficient under transient thermalisation conditions are then examined. Attention is next turned to the low-temperature "variable range" hopping regime. The conceptual error in the derivation of the "Mott T-1/4" law is reviewed, and a new approach is then advanced. This is shown to be in very good agreement with the simulation data, in respect of the dominant hopping distance and the density of states close to the Fermi level. Finally, we question whether any such model can be expected to yield meaningful results, when applied to experimental data..

Keywords

Disordered semiconductors, Variable range hopping, Mobility, Diffusion.

Submitted at: Nov. 1, 2006
Accepted at: Jan. 15, 2007

Citation

J. M. MARSHALL, Computer simulation studies of low-temperature hopping in spatially and energetically disordered systems, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 1, pp. 84-91 (2007)