Deposition of SnO2 as a functional layer on a porous silicon substrate for potential tandem solar cell application

The article presents the results of a SnO2 layer deposition, selected for its properties to function as either a recombination layer or an electron transporting material (ETM) layer in a potential silicon/perovskite tandem solar cell. The layer was deposited using an atomic layer deposition (ALD) method to ensure uniform coverage on the rough surface of etched silicon nanowires. The deposition process was monitored using test samples on glass by assessing surface roughness with an atomic force microscopy method and a total transmission through UV-VIS spectroscopy. The test layers were further characterised to estimate thickness using ellipsometry. The target layers, deposited on the porous surface of etched silicon nanowires, were examined using high-resolution scanning electron microscopy and transmission electron microscopy to evaluate the material microstructure, layer adhesion to the substrate, and the accuracy of ALD deposition on highly porous structures.