Silicon Powder-Based Wafers for Low-Cost Photovoltaics: Laser Treatments and Nanowire Etching

• Published in: International Journal of Photoenergy Vol. 2018; no. 2018; pp. 1 - 7
• Main Authors: Andrä, G., Ulyashin, A., Dellith, A., Carvalho, P. A., Syvertsen, M., Stokkan, G., Azar, Amin S., Gawlik, A., Plentz, J., Jia, G., Dellith, J.
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 01.01.2018; Hindawi; John Wiley & Sons, Inc; Wiley
• Subjects: Applied physics; Chemical etching; Crystallization; Electron beams; Etching; Hot pressing; Irradiation; Laser beams; Lasers; Liquid phases; Nanowires; Organic chemistry; Photonics; Photovoltaic cells; Powders; Quality; Raw materials; Sawing; Silicon; Silicon substrates; Silicon wafers; Sintering (powder metallurgy); Solar cells; Solar energy; Solar energy industry; Texturing; Thin films; Wafers
• ISSN: 1110-662X; 1687-529X
• DOI: 10.1155/2018/6563730

In this study, laser-treated polycrystalline Si (pc-Si) wafers, fabricated by wire sawing of hot-pressed ingots sintered from Si powder, have been investigated. As-cut wafers and those with high-quality thin Si layers deposited on top of them by e-beam have been subjected to laser irradiation to clarify typical trends of structural modifications caused by laser treatments. Moreover, possibility to use laser-treated Si powder-based substrates for fabrication of advanced Si structures has been analysed. It is established that (i) Si powder-based wafers with thicknesses ~180 μm can be fully (from the front to back side) or partly (subsurface region) remelted by a diode laser and grain sizes in laser-treated regions can be increased; (ii) a high-quality top layer can be fabricated by crystallization of an additional a-Si layer deposited by e-beam evaporation on top of the pc-Si; and (iii) silicon nanowires can be formed by metal-assisted wet chemical etching (MAWCE) of polished Si powder-based wafers and as-cut wafers irradiated with medium laser power, while a surface texturing on the as-cut pc-Si wafers occur, and no nanowires can form in the region subject to a liquid phase crystallization (LPC) caused by high-power laser treatments.