Structural and optoelectronical characterization of Si-SiO2/SiO2 multilayers with applications in all Si tandem solar cells

SiO2 multilayers with embedded Si nanocrystals Si-ncs were investigated as an approach for developing highly efficient all Si tandem solar cells. The nanostructured samples, fabricated by means of a reactive magnetron sputtering, were structurally and optoelectronically characterized using different techniques. High resolution transmission electron microscopy TEM and energy filtered images in TEM show a high density of Si-nc with uniform sizes below 4 nm, while electrical characterization indicates high resistance values 100 kOhm of these samples. In order to develop a better understanding of the optoelectronical behavior, photocurrent I-V curves were measured, obtaining variations under “dark” or “illumination” conditions. Recombination lifetimes in the order of tenths of nanoseconds were estimated by applying the transverse pump/probe technique.