Physics of the Meyer-Neldel Rule in Amorphous Silicon

Abstract

ABSTRACTWe show that the meyer-Neldel Rule (or compensation law) arises from the entropy effect of accumulating several excitations in order to surmount an activation barrier. This explanation applies both to annealing and to conductivity phenomena in a-Si:H. We consider three consequences of this theory for a-Si:H : 1) MN processes in a-Si:H involve coupling to a bath of “optical” phonons; 2) dc conductivity involves strongly electron-phonon coupled states rather than extended electrons and a fixed density of states; and 3) time-of-flight exponents depend upon the MN temperature.