MICROSCOPIC MODEL OF METASTABLE CHANGES IN HYDROGENATED AMORPHOUS-SILICON

Concepts based on the two‐level system of structural excitations have not accounted satisfactorily for many metastable changes in hydrogenated amorphous silicon. Defects created at higher temperatures are more difficult to anneal out. Photoluminescence decreases much more after irradiation at 77 K than it does after irradiation at 300 K. After rapid cooling from 483 K, the spin signal grows with time at room temperature, etc. A microscopic explanation of these and other phenomena is given in terms of a three‐level system of structural excitations: initial state, weak SiSi bond; intermediate metastable state, SiHSi bond; final metastable state, SiH and Si dangling bond. Copyright © 1990 WILEY‐VCH Verlag GmbH & Co. KGaA