Light trapping and photon management in honeycomb-textured microcrystalline silicon solar cells are investigated experimentally and by modeling of the manufacturing process and the optical wave propagation. The solar cells on honeycombtextured substrates exhibit short circuit current densities exceeding 30 mA/cm 2 and energy conversion efficiencies of up to 11.0%. By controlling the fabrication process, the period and height of the honeycomb-textured substrates are varied. The influence of the honeycomb substrate morphology on the interfaces of the individual solar cell layers and the quantum efficiency is determined. The optical wave propagation is calculated using 3D finite difference time domain simulations. A very good agreement between the optical simulation and experimental results is obtained. Strategies are discussed on how to increase the short circuit current density beyond 30 mA/cm 2 . In particular, the influence of plasmonic losses of the textured silver (Ag) reflector on the short circuit current and quantum efficiency of the solar cell is discussed. Finally, solar cell structures with reduced plasmonic losses are proposed.

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Light trapping and photon management of silicon thin film solar cells can be improved by a separate optimization of the front and back contact textures. A separate optimization of the front and back contact textures is investigated by optical simulations taking realistic device geometries into consideration. The optical simulations are confirmed by experimentally realized 1 μm thick microcrystalline silicon solar cells. The different front and back contact textures lead to an enhancement of the short circuit current by 1.2 mA/cm2 resulting in a total short circuit current of 23.65 mA/cm2 and an energy conversion efficiency of 8.35%.

optical losses. [8][9][10][11][12][13][14] Hence, both the quantum efficiency (QE) and short-circuit current density of the solar cells can potentially be enhanced when properly implemented. Several experimental and simulation approaches have been carried out to derive the optimal textured interfaces. [4,7,9,15] However, realization and modeling of the optimal textured interfaces are complex because several factors have to be considered. [4,7,9,15] In order to realize the solar cells with high energy conversion efficiency, it is necessary to maximize the product of short-circuit current density, open-circuit voltage, and fill factor. Texturing the interfaces affects not only the short-circuit current density. The open-circuit voltage and fill factor are affected too by changing the surface texture of microcrystalline silicon thinfilm solar cells. [2,7,[16][17][18][19][20][21][22][23][24][25][26] Microcrystalline silicon films grown on textured surfaces exhibit a high concentration of microstructure-induced recombination centers, while the silicon films prepared on smooth surfaces do not exhibit such microstructure-induced recombination centers. [16,18,[23][24][25][26] A high concentration of recombination centers is observed in regions with reduced structural order, often called "cracks" or "voids." The concentration of cracks increases with increasing roughness of the substrate. [14,16,18,[23][24][25][26] As a result, the crack formation affects the charge collection efficiency of the solar cells. Furthermore, the open-circuit voltage and fill factor are affected. [7,16,18,[22][23][24][25][26] Hence, these electrical properties of the microcrystalline silicon solar cell have to be considered when optimizing its light-trapping properties.The microcrystalline silicon (µc-Si:H) solar cells fabricated on hexagonal textured substrates exhibit the highest short-circuit current density of up to 32.9 mA cm −2 , and energy conversion efficiency up to 11.8%. [3,6] The highest short-circuit current density of 32.9 mA cm −2 is obtained for a 4 µm thick solar cell on a hexagonal textured substrate with period of 4 µm, while the highest energy conversion efficiency is obtained for a solar cell with a thickness of 1.7 µm on a hexagonal textured substrate with a period of 2.0 µm. [3,6] However, it remains unclear if hexagonal textured substrates represent the best possible substrate. Hence, in this study, the influence of different textured substrates on the QE, short-circuit current density, and formation of cracks is studied.In the following, the µc-Si:H solar cells with different substrate textures are compared in respect of the optical properties Microcrystalline silicon thin-film solar cells prepared on hexagonal tiled surfaces exhibit record short-circuit current densities and energy conversion efficiencies. However, it remains unclear if hexagonal textured substrates represent the best possible substrate tiling. In this study, hexagonal tiled substrates are compared with square and triangular tiled substrates in terms of...