Modulated surface texturing of temporary Al foils substrates for high-efficiency thin-film, flexible solar cells

In this work we focus on texturing Al substrate in order to employ the modulated surface texturing approach for thin-film, flexible, micromorph solar cells. We deployed two different methods to induce micro-craters in Al foil, i) bare Al etching by KOH and ii) AZO sacrificial layer etched in KOH. After modelling the etching kinetics of KOH on Al, we characterized the 2D correlation length and rms roughness of these samples and find the optimal aspect ratio of ~12% to deposit high-quality 3 µm-thick nc-Si. Finally, excellent angular scattering properties have been measured for both employed methods.