The Experts below are selected from a list of 38913 Experts worldwide ranked by ideXlab platform
Carsten Agert - One of the best experts on this subject based on the ideXlab platform.
-
Amorphous Silicon Oxinitride in Silicon Thin-film Solar Cells
Energy Procedia, 2014Co-Authors: Cordula Walder, Oleg Sergeev, Karsten Von Maydell, Alex Neumüller, M. Kellermann, Carsten AgertAbstract:Abstract Silicon oxide is a promising material for silicon thin-film solar cells. As a doped Layer it shows low parasitic absorption while as an Intrinsic Layer it can be used as a high band gap absorber in multijunction solar cells. Whereas doped silicon oxide Layers prepared with CO 2 are widely investigated, Intrinsic Layers and the use of N 2 O as a source gas for oxygen incorporation in silicon thin-film solar cells have not received much attention yet. Therefore we present the optical and electrical properties of doped and Intrinsic silicon oxinitride Layers at varying N 2 O flow as well as their performance in single cells. We found that p-doped amorphous silicon oxinitride Layers enhance the short circuit current and the open circuit voltage of amorphous silicon single cells while the fill factor is reduced due to higher series resistance. When N 2 O is added to the Intrinsic Layer of amorphous silicon single cells the cell performance deteriorates drastically which is attributed to increased defect density.
-
Simulation of single-junction thin-film silicon solar cells with varying Intrinsic Layer thickness
2012 38th IEEE Photovoltaic Specialists Conference, 2012Co-Authors: Stefan Geißendörfer, Cordula Walder, Oleg Sergeev, Karsten Von Maydell, Carsten AgertAbstract:Optical and electrical simulation is an economical method for optimizing the Layer thicknesses of silicon based thin-film solar cells. However, the used electrical parameter set must be verified for different Layer stack configurations to calibrate the modeling system. In this contribution we present an electrical parameter set as input data, which is able to model dark and illuminated IV-curves and EQE-spectra of a-Si:H single junction solar cells with different Intrinsic Layer thicknesses. Only few parameters are varied to align the experimental characteristics of the solar cells.
Q. Zhang - One of the best experts on this subject based on the ideXlab platform.
-
decoupling crystalline volume fraction and voc in microcrystalline silicon pin solar cells by using a µc si f h Intrinsic Layer
Physica Status Solidi-rapid Research Letters, 2008Co-Authors: Q. Zhang, Erik V. Johnson, Y. Djeridane, A. Abramov, Roca P I CabarrocasAbstract:Microcrystalline silicon thin film pin solar cells with a highly crystallized Intrinsic μc-Si:F:H absorber were prepared by RF-plasma enhanced chemical vapour deposition using SiF 4 as the gas precursor. The cells were produced with a vacuum break between the doped Layer and Intrinsic Layer depositions, and the effect of different subsequent interface treatment processes was studied. The use of an Intrinsic μc-Si:H p/i buffer Layer before the first air break increased the short circuit current density from 22.3 mA/cm 2 to 24.7 mA/cm 2 . However, the use of a hydrogen-plasma treatment after both air breaks without an interface buffer Layer improved both the open circuit voltage and the fill factor. Although the material used for the absorber Layer showed a very high crystalline fraction and thus an increased spectral response at long wavelengths, an open-circuit voltage (V oc ) of 0.523 V was nevertheless observed. Such a value of V oc is higher than is typically obtained in devices that employ a highly crystallized absorber as reported in the literature (see abstract figure). Using a hydrogen-plasma treatment, a single junction μc-Si:F:H pin solar cell with an efficiency of 8.3% was achieved.
-
Decoupling crystalline volume fraction and VOC in microcrystalline silicon pin solar cells by using a µc‐Si:F:H Intrinsic Layer
physica status solidi (RRL) - Rapid Research Letters, 2008Co-Authors: Q. Zhang, Erik V. Johnson, Y. Djeridane, A. Abramov, P. Roca I CabarrocasAbstract:Microcrystalline silicon thin film pin solar cells with a highly crystallized Intrinsic μc-Si:F:H absorber were prepared by RF-plasma enhanced chemical vapour deposition using SiF 4 as the gas precursor. The cells were produced with a vacuum break between the doped Layer and Intrinsic Layer depositions, and the effect of different subsequent interface treatment processes was studied. The use of an Intrinsic μc-Si:H p/i buffer Layer before the first air break increased the short circuit current density from 22.3 mA/cm 2 to 24.7 mA/cm 2 . However, the use of a hydrogen-plasma treatment after both air breaks without an interface buffer Layer improved both the open circuit voltage and the fill factor. Although the material used for the absorber Layer showed a very high crystalline fraction and thus an increased spectral response at long wavelengths, an open-circuit voltage (V oc ) of 0.523 V was nevertheless observed. Such a value of V oc is higher than is typically obtained in devices that employ a highly crystallized absorber as reported in the literature (see abstract figure). Using a hydrogen-plasma treatment, a single junction μc-Si:F:H pin solar cell with an efficiency of 8.3% was achieved.
Cordula Walder - One of the best experts on this subject based on the ideXlab platform.
-
Amorphous Silicon Oxinitride in Silicon Thin-film Solar Cells
Energy Procedia, 2014Co-Authors: Cordula Walder, Oleg Sergeev, Karsten Von Maydell, Alex Neumüller, M. Kellermann, Carsten AgertAbstract:Abstract Silicon oxide is a promising material for silicon thin-film solar cells. As a doped Layer it shows low parasitic absorption while as an Intrinsic Layer it can be used as a high band gap absorber in multijunction solar cells. Whereas doped silicon oxide Layers prepared with CO 2 are widely investigated, Intrinsic Layers and the use of N 2 O as a source gas for oxygen incorporation in silicon thin-film solar cells have not received much attention yet. Therefore we present the optical and electrical properties of doped and Intrinsic silicon oxinitride Layers at varying N 2 O flow as well as their performance in single cells. We found that p-doped amorphous silicon oxinitride Layers enhance the short circuit current and the open circuit voltage of amorphous silicon single cells while the fill factor is reduced due to higher series resistance. When N 2 O is added to the Intrinsic Layer of amorphous silicon single cells the cell performance deteriorates drastically which is attributed to increased defect density.
-
Simulation of single-junction thin-film silicon solar cells with varying Intrinsic Layer thickness
2012 38th IEEE Photovoltaic Specialists Conference, 2012Co-Authors: Stefan Geißendörfer, Cordula Walder, Oleg Sergeev, Karsten Von Maydell, Carsten AgertAbstract:Optical and electrical simulation is an economical method for optimizing the Layer thicknesses of silicon based thin-film solar cells. However, the used electrical parameter set must be verified for different Layer stack configurations to calibrate the modeling system. In this contribution we present an electrical parameter set as input data, which is able to model dark and illuminated IV-curves and EQE-spectra of a-Si:H single junction solar cells with different Intrinsic Layer thicknesses. Only few parameters are varied to align the experimental characteristics of the solar cells.
Miro Zeman - One of the best experts on this subject based on the ideXlab platform.
-
Determination of the mobility gap of Intrinsic μc-Si:H in p-i-n solar cells
Journal of Applied Physics, 2009Co-Authors: Bart E. Pieters, Miro Zeman, Helmut Stiebig, R.a.c.m.m. Van SwaaijAbstract: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 to the bandgap of crystalline silicon. However, in other studies mobility gap values have been reported to be in the range of 1.48–1.59?eV, depending on crystalline volume fraction. Indeed, for the accurate modeling of ?c-Si:H solar cells, it is paramount that key parameters such as the mobility gap are accurately determined. A method is presented to determine the mobility gap of the Intrinsic Layer in a p-i-n device from the voltage-dependent dark current activation energy. We thus determined a value of 1.19?eV for the mobility gap of the Intrinsic Layer of an ?c-Si:H p-i-n device. We analyze the obtained results in detail through numerical simulations of the ?c-Si:H p-i-n device. The applicability of the method for other than the investigated devices is discussed with the aid of numerical simulations
-
The Role of Charged Gap States in Light-Induced Degradation of Single-Junction a-Si:H Solar Cells
MRS Proceedings, 2004Co-Authors: Miro Zeman, V. Nadazdy, J.w. MetselaarAbstract:ABSTRACTComputer simulations of single-junction hydrogenated amorphous silicon (a-Si:H) solar cells with different thickness of the Intrinsic Layer were carried out in order to study the role of charge gap states in their light-induced degradation. It is demonstrated that it is the decrease of positively charged states above midgap, Dh, and the increase of neutral states around midgap,Dz, and negatively charged states below midgap, De in the Intrinsic Layer that result in a drop of performance of the solar cells due to light soaking. These changes in the gap states are in accordance with our recent experimental results from the charge deep-level transient spectroscopy on undoped a-Si:H. The experimentally observed changes in the dark and illuminated J-V curves and spectral response could not be simulated with the same set of input parameters by only increasing the defect-state density in the Intrinsic Layer.
-
Computer modelling of current matching in a-Si : H/a-Si : H tandem solar cells on textured TCO substrates
Solar Energy Materials and Solar Cells, 1997Co-Authors: Miro Zeman, G Tao, J.a. Willemen, L. L. A. Vosteen, J.w. MetselaarAbstract:Computer modelling is used as a tool for optimising a-Si : H/a-Si : H tandem cells on textured substrate in order to achieve current matching between the top and bottom cell. To take light scattering at the textured interfaces of the cell into account, we developed a multi-rough-interface optical model which was used for calculating the absorption profiles in the tandem cells. In order to simulate multi-junction solar cell as a complete device we implemented a novel model for tunnel/recombination junction (TRJ), which combines the trap-assisted tunnelling and enhanced carrier transport in the high-field region of the TRJ. We investigated the influence of light scattering and thickness of the Intrinsic Layer of the bottom cell on the optimal ratio i2/i1 between the thicknesses of the bottom (i2) and top (i1) Intrinsic Layers in the current-matched cell. The simulation results show that increasing amount of scattering at the textured interfaces leads to a lower ratio i2/i1 in the current-matched cell. This ratio depends on the thickness of the Intrinsic Layer of the bottom cell. The simulation results demonstrate that a-Si : H/a-Si : H tandem cell with 300 nm thick Intrinsic Layer in the bottom cell exhibits higher efficiency than the cell with 500 nm thick bottom Intrinsic Layer.
Swati Ray - One of the best experts on this subject based on the ideXlab platform.
-
Nanocrystalline silicon as Intrinsic Layer in thin film solar cells
Solid State Communications, 1998Co-Authors: Sukti Hazra, Swati RayAbstract:Abstract Nanocrystalline silicon (nc-Si) material is a potential candidate in photoluminescence and electroluminescence devices. So far, nc-Si thin films have had no applications in solar cells as Intrinsic Layers because of their non-photoconductive nature. In the present work, a new type of photoconductive nc-Si thin film has been developed by utilizing commercially compatible plasma enhanced chemical vapour deposition technique. Transmission electron micrographs of the new material gave evidence for the presence of scattered nanocrystallites of average size∽10 nm embedded in the hydrogenated amorphous silicon matrix. The photosensitivity of the nc-Si films is > 1×10 5 . To test the viability of the new material in devices, a p–i–n solar cell has been fabricated using the nc-Si material of optical gap 1.89eV, as the Intrinsic Layer. The efficiency of this single junction solar cell in 8.7%.
