Abstract: | |
We investigate the optical properties of n- and p-type polycrystalline silicon (poly-Si) layers. We determine the optical constants n and k of the complex refractive index of polycrystalline silicon by using variable-angle spectroscopic ellipsometry. Moreover, we investigate the effect of different doping levels in the poly-Si on free carrier absorption (FCA). Thereby, we demonstrate that the FCA in poly-Si can be described by a model developed for crystalline silicon (c-Si) at a first approximation. The optical properties of hydrogenated amorphous silicon layers (a-Si:H) are also investigated as a reference. With ray tracing simulations the absorption losses of poly-Si and of the a-Si:H layers are quantified with respect to the film thickness. Based on this approach we find that the short-circuit current density losses due to parasitic absorption of poly-Si layers are significantly lower when compared to a-Si:H layers of the same thickness. For example the short-circuit current density loss due to a 20 nm thick p-type poly-Si layer is around 1.1 mA/cm2, whereas a 20 nm thick p-type a-Si:H layer leads to a loss of around 3.5 mA/cm2.
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License of this version: | CC BY-NC-ND 4.0 Unported - https://creativecommons.org/licenses/by-nc-nd/4.0/ |
Publication type: | Article |
Publication date: | 2016 |
Keywords english: | front junction, optical properties, Polycrystalline silicon, ray tracing simulations, Amorphous materials, Crystalline materials, Optical properties, Polycrystalline materials, Polysilicon, Refractive index, Semiconductor doping, Silicon, Spectroscopic ellipsometry, Complex refractive index, Crystalline silicons, Free carrier absorption, Polycrystalline silicon (poly-Si), Polycrystalline-Si, Ray tracing simulation, Variable angle spectroscopic ellipsometry, Amorphous silicon |
DDC: | 530 | Physik |
Controlled keywords(GND): | Konferenzschrift |
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