Modeling photoluminescence spatial mapping of an isolated defect under uniform and selective excitation

In this work, two different excitation/detection modes, U/L mode and L/L mode for probing an extended defect are compared and discussed. A contrast function is introduced to describe the influence of the defect. We have found that the contrast function not only depends on dimensionality of the system (1-D vs. 2-D), but also depends on the excitation/detection mode. Photoluminescence mapping data using the two modes to study an isolated defect in GaAs are analyzed using our models. The results suggest that the L/L mode can, in principle, offer significantly better spatial resolution than the U/L mode.