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Christophe Ballif

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Related publications (443)

Parasitic absorption in the rear reflector of a silicon solar cell: Simulation and measurement of the sub-bandgap reflectance for common dielectric/metal reflectors

The rear side of a silicon solar cell is often designed to minimize surface recombination, series resistance, and cost, but not necessarily parasitic absorption. We present a comprehensive study of parasitic absorption in the metal layer of solar cells wit ...

Elsevier Science Bv2014

Hydrogen plasma treatment for improved conductivity in amorphous aluminum doped zinc tin oxide thin films

Christophe Ballif, Aïcha Hessler-Wyser, Laura Ding, Sylvain Nicolay, Quentin Thomas Jeangros, Fabien Paul Jacques Dauzou, Monica Morales Masis

Improving the conductivity of earth-abundant transparent conductive oxides (TCOs) remains an important challenge that will facilitate the replacement of indium-based TCOs. Here, we show that a hydrogen (H-2)-plasma post-deposition treatment improves the co ...

Amer Inst Physics2014

Silicon oxide buffer layer at the p-i interface in amorphous and microcrystalline silicon solar cells

Christophe Ballif, Mathieu Charrière, Gaetano Parascandolo, Grégory Bugnon, Matthieu Despeisse, Michael Elias Stückelberger

The use of intrinsic silicon oxide as a buffer layer at the p-i interface of thin-film silicon solar cells is shown to provide significant advantages. For microcrystalline silicon solar cells, when associated with highly crystalline i-layers deposited at h ...

Elsevier2014

Fabrication and characterization of monolithically integrated microchannel plates based on amorphous silicon

Christophe Ballif, Nicolas Würsch, Jonas Geissbühler, Andrea Franco

Microchannel plates are vacuum-based electron multipliers for particle—in particular, photon— detection, with applications ranging from image intensifiers to single-photon detectors. Their key strengths are large signal amplification, large active area, mi ...

Nature Publishing Group2014

9.4% Efficient Amorphous Silicon Solar Cell on High Aspect-Ratio Glass Microcones

Christophe Ballif, Mathieu Charrière, Corsin Battaglia, Hyunjung Park

High aspect-ratio three-dimensional (3D) a-Si:H solar cells have been fabricated to enhance a light absorption path while maintaining a short carrier collection length. Substantial efficiency enhancement in 3D solar cells was achieved due to the boost in J ...

Wiley-Blackwell2014

Amorphous silicon oxide window layers for high-efficiency silicon heterojunction solar cells

Christophe Ballif, Antoine Descoeudres, Stefaan De Wolf, Johannes Peter Seif

In amorphous/crystalline silicon heterojunction solar cells, optical losses can be mitigated by replacing the amorphous silicon films by wider bandgap amorphous silicon oxide layers. In this article, we use stacks of intrinsic amorphous silicon and amorpho ...

American Institute of Physics2014

Amorphous Silicon/Crystalline Silicon Heterojunction Solar Cells

Christophe Ballif, Antoine Descoeudres, Stefaan De Wolf

Silicon heterojunction solar cells are crystalline silicon-based devices in which thin amorphous silicon layers deposited on the wafer surfaces serve as passivated, carrier-selective contacts. The success of this technology is attributable to the ability o ...

Elsevier Academic Press Inc2014

High-Stable-Efficiency Tandem Thin-Film Silicon Solar Cell With Low-Refractive-Index Silicon-Oxide Interlayer

Christophe Ballif, Grégory Bugnon, Xavier Niquille, Mathieu Gérard Boccard, Matthieu Despeisse, Jordi Escarre Palou, Maximilien Joseph Marie Bonnet-Eymard

We report the recent advances and key requirements for high-efficiency "micromorph" tandem thin-film silicon solar cells composed of an amorphous silicon top cell and a microcrystalline silicon bottom cell. The impact of inserting a low-refractive-index si ...

Ieee-Inst Electrical Electronics Engineers Inc2014

Back-Contacted Silicon Heterojunction Solar Cells With Efficiency >21%

Christophe Ballif, Antoine Descoeudres, Stefaan De Wolf, Jonas Geissbühler, Andrea Tomasi, Bertrand Yves Paul Paviet-Salomon, Silvia Martin de Nicolas Agut

We report on the fabrication of back-contacted silicon heterojunction solar cells with conversion efficiencies above 21%. Our process technology relies solely on simple and size-scalable patterning methods, with no high-temperature steps. Using in situ sha ...

Ieee-Inst Electrical Electronics Engineers Inc2014

Technological status of plasma-deposited thin-film silicon photovoltaics

Christophe Ballif, Arvind Shah, Etienne Antoine Julien Moulin

Basic properties of plasma-deposited amorphous and microcrystalline layers are summarized. Limitations for solar cell performance, which are a result of these basic properties are pointed out. Efficiencies and other solar cell parameters obtained for the b ...

Elsevier2013

Optimized short-circuit current mismatch in multi-junction solar cells

Christophe Ballif, Fanny Sculati-Meillaud, Grégory Bugnon, Mathieu Gérard Boccard, Matthieu Despeisse, Maximilien Joseph Marie Bonnet-Eymard

Multi-junction photovoltaic devices include two or more component sub-cells which are electrically interconnected in series. At any power point, the current output of the total device is limited by the sub-cell with the smallest current density. Therefore, ...

Elsevier2013

Stencil-Nanopatterned Back Reflectors for Thin-Film Amorphous Silicon n-i-p Solar Cells

Christophe Ballif, Céline Pahud, Jürgen Brugger, Oscar Vazquez Mena, Andreea Veronica Savu, Mona Julia Katharina Klein, Franz-Josef Haug

We fabricated amorphous silicon n-i-p solar cells with two types of nanopatterned back reflectors using stencil lithography. One reflector type has a plasmonic grating that is embedded in the ZnO layer; the other one has a metallic grating patterned on top ...

Ieee-Inst Electrical Electronics Engineers Inc2013

Compositional study of defects in microcrystalline silicon solar cells using spectral decomposition in the scanning transmission electron microscope

Christophe Ballif, Martial Duchamp, Franz-Josef Haug

The chemical compositions of defective regions in microcrystalline thin film Si solar cells are studied using energy-dispersive X-ray spectroscopy and electron energy-loss spectroscopy (EELS) in the scanning transmission electron microscope. Nanometer-reso ...

American Institute of Physics2013

Super-Lambertian photocurrent-generation in solar cells with periodically textured interfaces

Christophe Ballif, Karin Söderström, Franz-Josef Haug, Ali Naqavi

We studied solar cells with periodic interface texture. For periods of 550 and 833 nm, we found that the measured photocurrent increases under oblique incidence and assumes a maximum between 20 and 30°. For the geometries used in our experiments, the initi ...

American Institute of Physics2013

Hydrogen-doped indium oxide/indium tin oxide bilayers for high-efficiency silicon heterojunction solar cells

Christophe Ballif, Antoine Descoeudres, Nicolas Badel, Stefaan De Wolf, Corsin Battaglia, Loris Barraud

The front transparent conductive oxide layer is a source of significant optical and electrical losses in silicon heterojunction solar cells because of the trade-off between free-carrier absorption and sheet resistance. We demonstrate that hydrogen-doped in ...

Elsevier2013

Amorphous/crystalline silicon interface defects induced by hydrogen plasma treatments

Christophe Ballif, Bénédicte Demaurex, Duncan Thomas Lindsay Alexander, Stefaan De Wolf, Loris Barraud, Jonas Geissbühler, Johannes Peter Seif

Excellent amorphous/crystalline silicon interface passivation is of extreme importance for high-efficiency silicon heterojunction solar cells. This can be obtained by inserting hydrogen-plasma treatments during deposition of the amorphous silicon passivati ...

American Institute of Physics2013

Hybrid axial and radial Si-GaAs heterostructures in nanowires

Christophe Ballif, Anna Fontcuberta i Morral, Martin Heiss, Sylvain Dunand, Daniel Rüffer, Sonia Conesa Boj, Eleonora Russo

Hybrid structures are formed from materials of different families. Traditionally, group IV and III-V semiconductors have not been integrated together in the same device or application. In this work we present a new approach for obtaining Si-GaAs hybrid het ...

Royal Society of Chemistry2013

Light trapping in solar cells at the extreme coupling limit

Christophe Ballif, Hans Peter Herzig, Franz-Josef Haug, Ali Naqavi, Corsin Battaglia

We calculate the maximal absorption enhancement obtainable by guided mode excitation in a weakly absorbing dielectric slab over wide wavelength ranges. The slab mimics thin film silicon solar cells in the low absorption regime. We consider simultaneously w ...

Optical Soc Amer2013

Ethanol-enriched low-pressure chemical vapor deposition ZnO bilayers: Properties and growth-A potential electrode for thin film solar cells

Christophe Ballif, Laura Ding, Sylvain Nicolay, Grégory Bugnon

Ethanol is used as a precursor during the growth of zinc oxide (ZnO) by low-pressure chemical vapor deposition (LPCVD). By adding ethanol, the surface of the deposited ZnO layer is flattened and its roughness is decreased about sevenfold. The layers become ...

American Institute of Physics2013

High-performance tandem silicon solar cells on F:SnO2

Christophe Ballif, Laura Ding, Sylvain Nicolay

High-performance transparent conducting oxides (TCOs) have significance for optimising PV performance. The efficiency of the resulting solar cells is dependent particularly on achieving high light scattering, low resistivity and low absorption (via low fre ...

Elsevier2013

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