Explanation of positive and negative PICTS peaks in SI-GaAs

摘要

A system of rate equations was used to study the unusual behavior of the EL2 defect in SI-GaAs. Experimental results show a strong correlation between the position of the Fermi level and the appearance of either negative or positive EL2 peaks. The applied model reproduces experimental results and provides a mechanism which explains the occurrence of negative EL2 peaks. Besides the numerical simulation we also adapted a simplified trap model which leads to a qualitative understanding of the negative PICTS peak effect. Furthermore, the existence of negative peaks can be viewed as evidence for the presence of a recombination center besides the EL2 in the analyzed samples.