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

Abstract

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 (102 kω) 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. © 2010 American Institute of Physics.