Interpretation of the activation energy derived from a stretched-exponential description of defect density kinetics in hydrogenated amorphous silicon

Abstract

At least three quantities have been referred to as ‘‘activation energies’’ in association with fits to metastable defect kinetics in hydrogenated amorphous silicon. Most commonly cited is Eτ, the activation energy determined from stretched-exponential fits to kinetics data measured over a range of temperatures. The stretched exponential can also be written in terms of a rate constant, K, which has been reported as being thermally activated. In addition, a stretched-exponential model describing defect kinetics includes an energy, E2, in its rate equation. In this article, we clarify the interpretations of Eτ, EK, and E2, and discuss the possible physical significance of Eτ.