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Nádazdy, V. (author), Zeman, M. (author)
journal article 2004
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Klaver, A. (author), Nádaždy, V. (author), Zeman, M. (author), Swaaiij, R.A.C.M.M. (author)
We present a study of changes in the defect density of states in hydrogenated amorphous silicon (a-Si:H) due to high-energy electron irradiation using charged deep-level transient spectroscopy. It was found that defect states near the conduction band were removed, while in other band gap regions the defect-state density increased. A similar...
journal article 2006
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Selker, J.S. (author), Thévenaz, L. (author), Huwald, H. (author), Mallet, A. (author), Luxemburg, W.M.J. (author), Van de Giesen, N. (author), Stejskal, M. (author), Zeman, J. (author), Westhoff, M. (author), Parlange, M.B. (author)
Instruments for distributed fiber-optic measurement of temperature are now available with temperature resolution of 0.01°C and spatial resolution of 1 m with temporal resolution of fractions of a minute along standard fiber-optic cables used for communication with lengths of up to 30,000 m. We discuss the spectrum of fiber-optic tools that may...
journal article 2006
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Pieters, B.E. (author), Stiebig, H. (author), Zeman, M. (author), Van Swaaij, R.A.C.M.M. (author)
Microcrystalline silicon (?c-Si:H) is a promising material for application in multijunction thin-film solar cells. A detailed analysis of the optoelectronic properties is impeded by its complex microstructural properties. In this work we will focus on determining the mobility gap of ?c-Si:H material. Commonly a value of 1.1?eV is found, similar...
journal article 2009
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Krc, J. (author), Zeman, M. (author), Luxembourg, S.L. (author), Topic, M. (author)
A concept of a modulated one-dimensional photonic-crystal (PC) structure is introduced as a back reflector for thin-film solar cells. The structure comprises two PC parts, each consisting of layers of different thicknesses. Using layers of amorphous silicon and amorphous silicon nitride a reflectance close to 100% is achieved over a broad...
journal article 2009
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Jarolimek, K. (author), De Groot, R.A. (author), De Wijs, G.A. (author), Zeman, M. (author)
We use a molecular-dynamics simulation within density-functional theory to prepare realistic structures of hydrogenated amorphous silicon. The procedure consists of heating a crystalline structure of Si64H8 to 2370 K, creating a liquid and subsequently cooling it down to room temperature. The effect of the cooling rate is examined. We prepared a...
journal article 2009
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Jäger, K. (author), Zeman, M. (author)
We present a mathematical model that relates the surface morphology of randomly surface-textured thin films with the intensity distribution of scattered light. The model is based on the first order Born approximation [see e.g., M. Born and E. Wolf, Principles of Optics, 7th ed. (Cambridge University Press, Cambridge, England, 1999) ] and on...
journal article 2009
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Westra, J.M. (author), Vavrunkova, V. (author), Sutta, P. (author), Van Swaaij, R.A.C.M.M. (author), Zeman, M. (author)
Thin-film poly-crystalline silicon (poly c-Si) on glass obtained by crystallization of an amorphous silicon (a-Si) film is a promising material for low cost, high efficiency solar cells. Our approach to obtain this material is to crystallize a-Si films on glass by solid phase crystallization (SPC). As the grain size of SPC poly c-Si films will...
journal article 2010
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Isabella, O. (author), Kr?, J. (author), Zeman, M. (author)
Substrates with a modulated surface texture were prepared by combining different interface morphologies. The spatial frequency surface representation method is used to evaluate the surface modulation. When combining morphologies with appropriate geometrical features, substrates exhibit an increased scattering level in a broad wavelength region....
journal article 2010
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Jarolimek, K. (author), De Groot, R.A. (author), De Wijs, G.A. (author), Zeman, M. (author)
We present a theoretical study of hydrogenated amorphous silicon nitride (a-SiNx:H), with equal concentrations of Si and N atoms (x=1), for two considerably different densities (2.0 and 3.0?g/cm3). Densities and hydrogen concentration were chosen according to experimental data. Using first-principles molecular-dynamics within density-functional...
journal article 2010
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Wank, M.A. (author), Van Swaaij, R.A.C.M.M. (author), Kudlacek, P. (author), Van de Sanden, M.C.M. (author), Zeman, M. (author)
We have applied pulse-shaped biasing to the expanding thermal plasma deposition of hydrogenated amorphous silicon at substrate temperatures ? 200?°C and growth rates around 1 nm/s. Substrate voltage measurements and measurements with a retarding field energy analyzer demonstrate the achieved control over the ion energy distribution for...
journal article 2010
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Lipovšek, B. (author), Kr?, J. (author), Isabella, O. (author), Zeman, M. (author), Topi?, M. (author)
Diffusive dielectric materials such as white paint have been demonstrated as effective back reflectors in the photovoltaic technology. In this work, a one-dimensional (1D) optical modeling approach for simulation of white paint films is developed and implemented in a 1D optical simulator for thin-film solar cells. The parameters of white paint,...
journal article 2010
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Zeman, M. (author)
journal article 2010
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Solntsev, S. (author), Zeman, M. (author)
In thin-film silicon solar cells (TFSC) efficient light management is essential in order to increase energy conversion efficiency. The application of nano-scale periodic gratings (PG) is a promising method to enhance absorption in the absorber layers of TFSC since they can efficiently scatter the incident light. Carefully designed gratings give...
journal article 2011
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Zhang, D. (author), Tavakoliyaraki, A. (author), Wu, Y. (author), Van Swaaij, R.A.C.M.M. (author), Zeman, M. (author)
Heterojunction silicon with intrinsic thin layer (HIT) solar cells that combine advanced thin-film hydrogenated amorphous silicon (a-Si:H) and crystalline silicon (c-Si) technologies are promising because of the high performance at low cost. Due to the low conductivity of a-Si:H, indium tin oxide (ITO) needs to be used as a front contact layer...
journal article 2011
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Jäger, K. (author), Schulte, K. (author), Bittkau, K. (author), Ermes, A.M. (author), Zeman, M. (author), Pieters, B.E. (author)
The scattering properties of transparent conductive oxide (TCO) layers are fundamentally related to the performance of thin film silicon solar cells. In this study we introduce an experimental technique to access light scattering properties at textured TCO-silicon interfaces. Therefore we prepared a sample with a polished microcrystalline...
conference paper 2011
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Schulte, M. (author), Bittkau, K. (author), Jäger, K. (author), Ermes, M. (author), Zeman, M. (author), Pieters, B.E. (author)
Textured interfaces in thin-film silicon solar cells improve the efficiency by light scattering. A technique to get experimental access to the angular intensity distribution (AID) at textured interfaces of the transparent conductive oxide (TCO) and silicon is introduced. Measurements are performed on a sample with polished microcrystalline...
journal article 2011
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De Haan, V. (author), Santbergen, R. (author), Tijssen, M. (author), Zeman, M. (author)
A study is presented giving the response of three types of fiber-optic interferometers by which a standing wave through an object is investigated. The three types are a Sagnac, Mach–Zehnder and Michelson–Morley interferometer. The response of the Mach–Zehnder interferometer is similar to the Sagnac interferometer. However, the Sagnac...
journal article 2011
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Kind, R. (author), Van Swaaij, R.A.C.M.M. (author), Rubinelli, F.A. (author), Solntsev, S. (author), Zeman, M. (author)
The performance of hydrogenated amorphous silicon (a-Si:H) p-i-n solar cells is limited, as they contain a relatively high concentration of defects. The dark current voltage (JV) characteristics at low forward voltages of these devices are dominated by recombination processes. The recombination rate depends on the concentration of active...
journal article 2011
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Jäger, K. (author), Fischer, M. (author), Van Swaaij, R.A.C.M.M. (author), Zeman, M. (author)
We present a scattering model based on the scalar scattering theory that allows estimating far field scattering properties in both transmission and reflection for nano-textured interfaces. We first discuss the theoretical formulation of the scattering model and validate it for nano-textures with different morphologies. Second, we combine the...
journal article 2012
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