A Study on Tetragonal-star Like Shaped Inverted Pyramid Texturing

Donercark E., ÇİFTPINAR E. H., TERLEMEZOĞLU M., Colakoglu T., TURAN R.

48th IEEE Photovoltaic Specialists Conference (PVSC), ELECTR NETWORK, 20 - 25 June 2021, pp.219-221 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Doi Number: 10.1109/pvsc43889.2021.9518944
  • Page Numbers: pp.219-221
  • Keywords: inverted pyramid, Cu-assisted etching, star-shaped, SILICON
  • Middle East Technical University Affiliated: Yes


Surface texturing is one of the key process steps in solar cell fabrication. For an ideal surface texturing, surface recombination should be kept as low as possible while the light trapping property is improved. The formation of a random inverted pyramids is a good candidate with its improved light trapping properties compared to standard upright pyramid texturing and its reduced surface roughness compared to nanowire texturing resulting in reduced surface recombination velocity. In this work, we investigate a single step, lithography-free, Cu-assisted inverted pyramid texturing resulting in significantly reduced surface reflection on p-type Cz-Si. With the help of randomly distributed star-shaped inverted pyramid texturing on p-type Si, the weighted average reflection was reduced to 3% for p-type Si between 400-1000 nm. As a first cell trial, standard Al-BSF cells were fabricated using industrial process tools on p-wafer with star-shaped IPs. The low-cost, effective and repeatable nature of the developed single-step etching process has a high potential to replace surface texturing steps in the large-scale solar cell production cycle. Due to the implantation of star-shaped inverted pyramids to Al-BSF Si solar cell fabrication, short circuit current density was improved by more than 3.5%, resulting in 39.1mA/cm(2).