Hydrogen Diffusion and Thermal Equilibrium of Electronic States in a-Si:H

Abstract

AbstractThis paper reviews the recent evidence for thermal equilibrium effects in the electronic behavior of hydrogenated amorphous silicon, and relates the thermally induced changes to the motion of bonded hydrogen. The electronic properties are studied through measurements of d.c conductivity and-.weep out, and the role of hydrogen is explored through its diffusion. The magnitude and doping dependence of the diffusion coefficient DH matches the data on the equilibration of the electronic states. Furthermore both the diffusibn and the relaxation can be described by the same dispersive time dependence. It is argued that the diffusion of hydrogen is the rate limiting step in the the equilibration mechanisms and determines the kinetics.