Assessing the Performance of Surface Passivation Using Low-Intensity Photoluminescence Characterization Techniques

This paper applies quasi-steady-state photoluminescence (QSS-PL) and photoluminescence imaging to characterize the recombination properties of various surface passivation techniques. Particular interest is given to the performance at low excess carrier densities where many types of surface passivation show a strong increase in surface recombination velocity. These techniques are then used to further understand the ability of parasitic effects such as nonuniform illumination, edge recombination and areas of high recombination to affect these measurements. Furthermore, a new technique for edge isolation using laser doping is shown to be effective against the effect of edge recombination. This technique is useful to implement when using QSS-PL to analyze small samples as carriers conducted to the edge regions can dramatically alter the effective lifetime in low injection.