Recherche

Afficher tous les résultats pour

Accueil

Personne

Stefaan De Wolf

Cette personne a quitté l’EPFL

À propos
Confidentialité
Mentions légales

Graph Chatbot

Publications associées (78)

Page 2 sur 4

Practical silicon deposition rules derived from silane monitoring during plasma-enhanced chemical vapor deposition

Christophe Ballif, Bénédicte Demaurex, Stefaan De Wolf

We clarify the difference between the SiH4 consumption efficiency eta and the SiH4 depletion fraction D, as measured in the pumping line and the actual reactor of an industrial plasma-enhanced chemical vapor deposition system. In the absence of significant ...

American Institute of Physics2015

Complex Refractive Index Spectra of CH3NH3PbI3 Perovskite Thin Films Determined by Spectroscopic Ellipsometry and Spectrophotometry

Christophe Ballif, Jun Ho Yum, Soo-Jin Moon, Stefaan De Wolf, Michael Elias Stückelberger, Jérémie Werner, Björn Niesen

The complex refractive index (dielectric function) of planar CH3NH3PbI3 thin films at room temperature is investigated by variable angle spectroscopic ellipsometry and spectrophotometry. Knowledge of the complex refractive index is essential for designing ...

Amer Chemical Soc2015

Amorphous silicon passivated contacts for diffused junction silicon solar cells

Aïcha Hessler-Wyser, Bénédicte Demaurex, Stefaan De Wolf

Carrier recombination at the metal contacts is a major obstacle in the development of high-performance crystalline silicon homojunction solar cells. To address this issue, we insert thin intrinsic hydrogenated amorphous silicon [a-Si: H(i)] passivating fil ...

American Institute of Physics2014

Zinc tin oxide as high-temperature stable recombination layer for mesoscopic perovskite/silicon monolithic tandem solar cells

Christophe Ballif, Sylvain Nicolay, Soo-Jin Moon, Arnaud Walter, Davide Sacchetto, Stefaan De Wolf, Xavier Niquille, Jérémie Werner, Monica Morales Masis, Björn Niesen, Philipp Friedrich Hermann Löper, Oscar Esteban Rucavado Leandro

Perovskite/crystalline silicon tandem solar cells have the potential to reach efficiencies beyond those of silicon single-junction record devices. However, the high-temperature process of 500 °C needed for state-of-the-art mesoscopic perovskite cells has, ...

American Institute of Physics2016

Attenuated total reflectance Fourier-transform infrared spectroscopic investigation of silicon heterojunction solar cells

Christophe Ballif, Stefaan De Wolf, Jakub Holovsky

Silicon heterojunction solar cells critically depend on the detailed properties of their amorphous/crystalline silicon interfaces. We report here on the use of attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy to gain precise ...

American Institute of Physics2015

Amorphous/Crystalline Silicon Interface Stability: Correlation between Infrared Spectroscopy and Electronic Passivation Properties

Christophe Ballif, Stefaan De Wolf, Jakub Holovsky, Silvia Martin de Nicolas Agut

Ultrathin layers of hydrogenated amorphous silicon (a-Si:H), passivating the surface of crystalline silicon (c-Si), are key enablers for high-efficiency silicon heterojunction solar cells. In this work, the authors apply highly sensitive attenuated total r ...

WILEY2020

Low-Temperature High-Mobility Amorphous IZO for Silicon Heterojunction Solar Cells

Christophe Ballif, Stefaan De Wolf, Jakub Holovsky, Monica Morales Masis

Parasitic absorption in the transparent conductive oxide (TCO) front electrode is one of the limitations of silicon heterojunction (SHJ) solar cells efficiency. To avoid such absorption while retaining high conductivity, TCOs with high electron mobility ar ...

Ieee-Inst Electrical Electronics Engineers Inc2015

Improved Optics in Monolithic Perovskite/Silicon Tandem Solar Cells with a Nanocrystalline Silicon Recombination Junction

Christophe Ballif, Aïcha Hessler-Wyser, Sylvain Nicolay, Quentin Thomas Jeangros, Stefaan De Wolf, Matthieu Despeisse, Jérémie Werner, Florent Sahli, Loris Barraud, Raphaël Monnard, Johannes Peter Seif, Andrea Tomasi, Bertrand Yves Paul Paviet-Salomon, Björn Niesen, Matthias Wolfgang Bräuninger

Perovskite/silicon tandem solar cells are increasingly recognized as promi-sing candidates for next-generation photovoltaics with performance beyond the single-junction limit at potentially low production costs. Current designs for monolithic tandems rely ...

2017

Efficient silicon solar cells with dopant-free asymmetric heterocontacts

Christophe Ballif, Stefaan De Wolf, Jonas Geissbühler

A salient characteristic of solar cells is their ability to subject photo-generated electrons and holes to pathways of asymmetrical conductivity-'assisting' them towards their respective contacts. All commercially available crystalline silicon (c-Si) solar ...

Nature Publishing Group2016

Amorphous/Crystalline Silicon Interface Passivation: Ambient-Temperature Dependence and Implications for Solar Cell Performance

Christophe Ballif, Bénédicte Demaurex, Stefaan De Wolf, Johannes Peter Seif

Silicon heterojunction (SHJ) solar cells feature amorphous silicon passivation films, which enable very high voltages. We report how such passivation increases with operating temperature for amorphous silicon stacks involving doped layers and decreases for ...

Ieee-Inst Electrical Electronics Engineers Inc2015

Strategies for Doped Nanocrystalline Silicon Integration in Silicon Heterojunction Solar Cells

Christophe Ballif, Aïcha Hessler-Wyser, Antoine Descoeudres, Stefaan De Wolf, Jonas Geissbühler, Johannes Peter Seif, Gizem Nogay, Martin Ledinsky

Carrier collection in silicon heterojunction (SHJ) solar cells is usually achieved by doped amorphous silicon layers of a few nanometers, deposited at opposite sides of the crystalline silicon wafer. These layers are often defect-rich, resulting in modest ...

Ieee-Inst Electrical Electronics Engineers Inc2016

Improved amorphous/crystalline silicon interface passivation by hydrogen plasma treatment

Christophe Ballif, Antoine Descoeudres, Benjamin Strahm, Bénédicte Demaurex, Stefaan De Wolf, Loris Barraud, Jakub Holovsky, Johannes Peter Seif

Silicon heterojunction solar cells have high open-circuit voltages thanks to excellent passivation of the wafer surfaces by thin intrinsic amorphous silicon (a-Si:H) layers deposited by plasma-enhanced chemical vapor deposition. We show a dramatic improvem ...

2011

Analysis of lateral transport through the inversion layer in amorphous silicon/crystalline silicon heterojunction solar cells

Christophe Ballif, Stefaan De Wolf

In amorphous/crystalline silicon heterojunction solar cells, an inversion layer is present at the front interface. By combining numerical simulations and experiments, we examine the contribution of the inversion layer to lateral transport and assess whethe ...

American Institute of Physics2013

Increasing the efficiency of silicon heterojunction solar cells and modules by light soaking

Christophe Ballif, Antoine Descoeudres, Jacques Levrat, Stefaan De Wolf, Franz-Josef Haug, Matthieu Despeisse

Silicon heterojunction solar cells use crystalline silicon (c-Si) wafers as optical absorbers and employ bilayers of doped/intrinsic hydrogenated amorphous silicon (a-Si:H) to form passivating contacts. Recently, we demonstrated that such solar cells incre ...

Elsevier Science Bv2017

Manufacturing 100-mu m-thick silicon solar cells with efficiencies greater than 20% in a pilot production line

Christophe Ballif, Antoine Descoeudres, Stefaan De Wolf

Reducing wafer thickness while increasing power conversion efficiency is the most effective way to reduce cost per Watt of a silicon photovoltaic module. Within the European project 20 percent efficiency on less than 100-mu m-thick, industrially feasible c ...

Wiley-VCH Verlag2015

Impact of organic overlayers on a-Si:H/c-Si surface potential

Christophe Ballif, Stefaan De Wolf, Johannes Peter Seif, Andrea Tomasi, Björn Niesen

Bilayers of intrinsic and doped hydrogenated amorphous silicon, deposited on crystalline silicon (c-Si) surfaces, simultaneously provide contact passivation and carrier collection in silicon heterojunction solar cells. Recently, we have shown that the pres ...

American Institute of Physics2017

Parasitic Absorption Reduction in Metal Oxide-Based Transparent Electrodes: Application in Perovskite Solar Cells

Christophe Ballif, Sylvain Nicolay, Ali Dabirian, Stefaan De Wolf, Jérémie Werner, Monica Morales Masis, Björn Niesen

Transition metal oxides (TMOs) are commonly used in a wide spectrum of device applications, thanks to their interesting electronic, photochromic, and electrochromic properties. Their environmental sensitivity, exploited for gas and chemical sensors, is how ...

Amer Chemical Soc2016

Transparent Electrodes in Silicon Heterojunction Solar Cells: Influence on Contact Passivation

Christophe Ballif, Sylvain Nicolay, Stefaan De Wolf, Florent Sahli, Loris Barraud, Johannes Peter Seif, Lorenzo Fanni, Andrea Tomasi, Bertrand Yves Paul Paviet-Salomon, Björn Niesen, Silvia Martin de Nicolas Agut

Charge carrier collection in silicon heterojunction solar cells occurs via intrinsic/doped hydrogenated amorphous silicon layer stacks deposited on the crystalline silicon wafer surfaces. Usually, both the electron and hole collecting stacks are externally ...

Ieee-Inst Electrical Electronics Engineers Inc2016

Modification of textured silicon wafer surface morphology for fabrication of heterojunction solar cell with open circuit voltage over 700mV

Christophe Ballif, Aïcha Hessler-Wyser, Stefaan De Wolf, Luc Fesquet

Crystalline silicon wafer (c-Si) can be extremely well passivated by plasma enhanced chemical vapor deposited (PECVD) amorphous silicon (a-Si:H) films. As a result, on flat substrates, solar cells with very high open circuit voltage are readily obtained. O ...

2010

Understanding of passivation mechanism in heterojunction c-Si solar cells

Stefaan De Wolf

Intrinsic hydrogenated amorphous silicon (a-Si:H) films can yield in outstanding electronic surface passivation of crystalline silicon (c-Si) wafers as utilized in the HIT (heterojunction with intrinsic thin layer) solar cells. We have studied the correlat ...

Materials Research Society2008