Morphology and optical properties of sputter deposited silver nanoparticles on plain, textured and antireflection layer coated textured silicon

Abstract

Silver nanoparticles (Ag NPs) are prepared on plain silicon (P-Si), textured silicon (T-Si), and silicon nitride coated textured silicon (Si3N4/T-Si) substrates using magnetron sputtering powered with RF and pulsed DC followed by thermal annealing at different temperatures. The Ag NPs size, shape and concentration are very sensitive to the silicon topology, material (Si/Si3N4), sputter power (DC/RF), and annealing temperature. In Ag NPs morphology study, we observed that P-Si favors bigger NPs growth compared to T-Si and Si3N4/T-Si substrates due to the variation in the silicon topography, and RF powered sputtering favors bigger NPs size compared to pulsed DC powered sputtering due to variation in the deposition rate. We have not observed much variation in Ag NPs sizes between T-Si and Si3N4/T-Si substrates. The light trapping in P-Si, T-Si and Si3N4/T-Si substrates after integrating Ag NPs are investigated using total reflectance and transmittance measurements. The excited Ag NPs’ surface plasmon resonances led to the wavelength dependent enhancement in light absorption as well as reflection in the polychromatic spectrum. Maximum reflectance reduction (∼8%) observed from T-Si integrated with Ag NPs, due to the simultaneous light interaction with textured micron scale Si and nano-scale Ag, in the entire wavelength region.