Evaluating plasmonic light trapping with photoluminescence

We use photoluminescence measurements to quantify the light trapping for a range of plasmonic structures. By combining Ag nanoparticles as a scattering structure and diffuse white paint as a back surface reflector (BSR) on silicon wafers, we can achieve absorption enhancement of 62% of the Lambertian value, which is comparable with literature values for inverted pyramids of 67%. Through measurements of the effective carrier lifetime, we also establish that plasmonic Ag particles do not degrade the electrical properties of the passivation layer.