Electron diffusion in bond-disordered media

A theory of electron motion over randomly situated centres is developed. The electron binding energy in the centres is assumed to be constant. By means of the concepts developed in percolation theory all the centres can be separated into two groups. The first group makes a diffusion cluster responsible for the macroscopic transport. The second group of centres, i.e. isolated centres plays the role of the sources owing to their electron exchange with the first type of centre. A modified diffusion equation is derived describing the electron motion in such a system. By means of this equation the electron motion in an external uniform electric field has been analysed. </jats:p