Light Trapping by Micro and Nano-hole Texturing of Single-crystalline Silicon Solar Cells

• Published in: Energy procedia 2016-08, Vol.92, p.291-296
• Main Authors: Altinoluk, Serra H., Ciftpinar, Hande E., Demircioglu, Olgu, Es, Firat, Baytemir, Gulsen, Akar, Orhan, Aydemir, Akin, Sarac, Adem, Akin, Tayfun, Turan, Rasit
• Format: Article
• Language: English
• Subjects: Light trapping; periodic hole texturing; texturing
• ISSN: 1876-6102; 1876-6102
• DOI: 10.1016/j.egypro.2016.07.081

The efficiency of a solar cell strongly depends on the interaction between the incoming light beam and the surface of the device. Any process enhances light-surface interaction increases absorption probability of the light; thus, improves generated current, in turn. Generated current could be improved either by light trapping or by increased device thickness. Considering fabrication costs and recombination losses, mechanically thin optically thick wafers are being focused on in terms of light trapping properties. Surface texturing among the other methods is an effective and more lasting technique in reducing reflections and improving light trapping. In order to maximize the absorption of light and the efficiency of the cell, various light trapping schemes have been proposed so far. In this study, texturing silicon (Si) wafer surface with periodic holes using two top-down fabrication techniques: Metal Assisted Etching (MAE) and Reactive Ion Etching (RIE) was focused on. Following the design of optical masks with patterns of different hole sizes and distributions, hole-textured surfaces with dimensions varying from micron scale to submicron scale were fabricated using both etching techniques. Hole-textured surfaces with desired hole depth values could be successfully fabricated. It was observed that surface having periodic holes with 4μm diameter, 5μm gap between holes and 8μm depth could result in 15.7% efficiency.