Nanostructured surfaces

Investigation of frontal functional nanolayers of solar silicon using electrochemical technologies of porous silicon
Skrypnyk I.I., Yerokhov V.Yu., Druzhinin A.A., Nichkalo S.I.
Department of Semiconductor Electronics, Lviv Polytechnic National University, 
S. Bandera Str., 12, Lviv-79013, Ukraine
E-mail: v.yerokhov@gmail.com

The study of all stages of formation of the porous structure based on the chosen technology and identification of patterns that affect the characteristics of the obtained nano-, meso- and macropores are very important, as most parameters of porous layers are laid at the initial stage. When using porous silicon as a textural and anti-reflective coating, the porous layer is formed directly on the surface of silicon and together with the antireflective coating. It must also provide passivation of the surface of the solar cell (SC).
Silicon surface texturing, both chemical and electrochemical etching, is an integral part of modern high-performance silicon SC technology. The texture on the front surface of the SC not only reduces reflection losses, but also helps to capture long-wavelength light in the structure of the SC, thereby expanding its operating spectral range and increasing the short-circuit current.
Electrochemical hydrogenation in hydrogen-enriched electrolytes may be a more effective method of improving the passivating properties of PSi [1]. With this treatment, efficient hydrogenation of broken bonds at the interface between PSi/monocrystalline, polycrystalline or multicrystalline silicon can be achieved, which will help reduce the rate of surface recombination. Compared with other methods of hydrogen saturation, electrochemical hydrogenation has a number of advantages. First, it can be combined with the anodizing process and does not complicate the technology of SC manufacturing. Second, electrochemical hydrogenation is a controlled process that allows hydrogen atoms to penetrate the semiconductor volume to a given depth and passivated broken bonds without damaging its crystal lattice. In order to improve the passivating properties of PSi layers used in SC, a study of the process of electrochemical hydrogenation of PSi was performed both on p-type silicon substrates with a resistivity of 0.1–10 Ω×cm and on substrates with formed emitter transition n+-p conductivity.

1.	Yerokhov V., Ierokhova O. Improved porous silicon-based multifunctional materials for the solar cells antireflection coating// International Conference on Electronics and Information Technology, EIT 2016 - Conference Proceedings, 7500990 (2016).