Decomposition of positron lifetime spectra generated by Monte Carlo method: The case study of 6H silicon carbide

Abstract

6H silicon carbide positron lifetime spectra consisting of different concentrations of carbon vacancy, silicon vacancy and divacancy were generated by Monte Carlo simulation. Although the lifetime spectra contained more than one defect, they were well fitted by the two component model with good chi squares. Artificial defect components were found to form by the merging of the different vacancy defects. For some of these cases, the invalidity of the simple trapping model could not be revealed by the commonly used τ b,mod test. This would lead to the mis-identification of virtual vacancy defects having characteristic lifetimes depending on the concentrations of the carbon vacancy, the silicon vacancy and the divacancy. © 2006 Elsevier B.V. All rights reserved.