Charge-Defect Thermodynamic Equilibrium and Metastable Defects in Amorphous Silicon

Abstract

ABSTRACTThe thermodynamic equilibrium framework first presented at the Spring ′91 MRS meeting is refined and applied. The effect of temperature on band gap is added, resulting in a larger estimate of the loss in entropy associated with dangling bond formation. The magnitude of the entropy loss is consistent with a structural rearrangement. At the temperatures of interest, dangling bond defect formation is exothermic with negative entropy and free energy changes. The thermodynamic framework was used to address some practical issues including the estimation of the saturated dangling bond density resulting from low temperature light soaking and the electronic energy levels of the various dangling bond charge states.