Book/Dissertation / PhD Thesis

FZJ-2017-02359

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Light Trapping by Light Treatment - Direct Laser Interference Patterning for theTexturing of Front Contacts in Thin-Film Silicon Solar Cells

Dyck, T. (Corresponding author)FZJ*

2017
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-208-5

Please use a persistent id in citations: http://hdl.handle.net/2128/14008

Abstract: To further increase the energy conversion efficiency of thin-film silicon solar cells, the minimization of reflection losses by effective light trapping is essential. Light trapping is achieved by introducing textured surfaces in the layer stack of a solar cell. The incoming light is scattered at the textured interfaces, the light paths within the absorber layer are enhanced and the chance of absorption rises. This work aims to develop an industrial feasible laser-based process for the texturing of the aluminium-doped zinc oxide (ZnO:Al) layer used as front contact in solar cells. While wet chemical etching of the ZnO:Al is an established process for the texturing, a laser-based process offers higher flexibility and controllability of texture scattering properties. Accordingly, the light trapping can be engineered to fit the needs of a solar cell. Within this work, five laser-based processing techniques are evaluated for their applicability to texture ZnO:Al layers in an industrial environment. The direct writing of textures is capable of producing the right feature sizes and is highly flexible. However, it has strong demands on the experimental setup and requires long processing times. Refocusing the laser light by a particle lens array as well as laser-induced chemical etching also lack the industrial feasibility due to the complex processing setup. The creation of laser-induced periodical surface structures (LIPSS) by ultra-short pulse lasers promises small feature sizes with a simple setup. However, the flexibility of feature sizes and shapes is limited. Only direct laser interference patterning (DLIP) is capable of producing a large variety of adjustable textures with right-sized features while being able to cover large areas in reasonable amounts of time with an industrial feasible processing setup. To further investigate DLIP processing, a highly exible three-beam interference setup was designed and implemented. Within the setup, the beam properties of the three partial beams can be adjusted completely independently. By controlling power, polarization and angle of incidence of the individual beams, the intensity distribution within the overlapping volume is adjusted. This intensity distribution then translates to a topography on the ZnO:Al sample. With one single laser pulse, hundreds of thousands strictly periodic micrometer and submicrometer-sized features are created. [...]

Note: RWTH Aachen, Diss., 2017

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Contributing Institute(s):

1. Photovoltaik (IEK-5)

Research Program(s):

1. 121 - Solar cells of the next generation (POF3-121) (POF3-121)

Appears in the scientific report 2017

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