Invited Paper HOPPING TRANSPORT IN AN ISOENERGETIC SPATIALLY-RANDOM ARRAY OF SITES- THE EFFECT OF JUMPS INTO DISTANT SITES

Semiconductors and insulators in which quantum mechanical tunnelling ("hopping") between localised sites is the dominant charge transport process are often characterised by appreciable disorder in the spatial positions of the sites, and usually by similar disorder in their energies. In this paper, we confine ourselves to the case of iso-energetic sites, and employ a Monte Carlo simulation technique to explore various aspects of the hopping process. In particular, we examine in detail the consequences of confining allowed transitions to a restricted number of nearby sites. It is shown that the assumptions and averaging procedures employed in various prior analytical approaches to the problem can have a much more profound effect than has been anticipated. The present study thus suggests that a re-consideration of such factors would be merited