Publications de Grégory Bugnon

Comparison of LPCVD and sputter-etched ZnO layers applied as front electrodes in tandem thin-film silicon solar cells

Christophe Ballif, Grégory Bugnon, Franz-Josef Haug, Michael Elias Stückelberger, Etienne Antoine Julien Moulin

Aluminum-doped zinc oxide (ZnO:Al) layers deposited by sputtering and boron-doped zinc oxide (ZnO:B) layers deposited by low-pressure chemical vapor deposition (LPCVD) are well-established materials for front electrodes in thin-film silicon solar cells. In ...

Elsevier2016

Amorphous silicon-germanium for triple and quadruple junction thin-film silicon based solar cells

Christophe Ballif, Grégory Bugnon, Franz-Josef Haug, Mathieu Gérard Boccard, Matthieu Despeisse, Michael Elias Stückelberger, Maximilien Joseph Marie Bonnet-Eymard, Björn Niesen

We study amorphous silicon-germanium (a-SiGe:H) as intrinsic absorber material for thin-film silicon-based triple and quadruple junction solar cells. First, we present the development of a-SiGe:H single junction devices, in particular the Ge-content gradin ...

Elsevier2015

The boron-tailing myth in hydrogenated amorphous silicon solar cells

Christophe Ballif, Grégory Bugnon, Franz-Josef Haug, Matthieu Despeisse, Michael Elias Stückelberger

The boron-tailing effect in hydrogenated amorphous silicon (a-Si:H) solar cells describes the reduced charge collection specifically in the blue part of the spectrum for absorber layers deposited above a critical temperature. This effect limits the device ...

AIP American Institute of Physics2015

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

Thin-Film Silicon Triple-Junction Solar Cells on Highly Transparent Front Electrodes With Stabilized Efficiencies up to 12.8%

Christophe Ballif, Grégory Bugnon, Franz-Josef Haug, Mathieu Gérard Boccard, Matthieu Despeisse, Michael Elias Stückelberger

High-efficiency thin-film silicon triple-junction solar cells in p-i-n configuration have been fabricated using amorphous silicon top cell absorber layers, as well as microcrystalline silicon middle and bottom cell absorbers. The triple-junction cells were ...

Ieee-Inst Electrical Electronics Engineers 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

Post-deposition treatment of microcrystalline silicon solar cells for improved performance on rough superstrates

Christophe Ballif, Laura Ding, Sylvain Nicolay, Grégory Bugnon, Mathieu Gérard Boccard

In this contribution, we investigate the effect of post-deposition treatments on finished non-encapsulated thin-film microcrystalline silicon solar cells and show that annealing in vacuum leads to improved electrical properties of the solar cells, particul ...

American Institute of Physics2014

Light trapping in thin-film solar cells measured by Raman spectroscopy

Christophe Ballif, Grégory Bugnon, Etienne Antoine Julien Moulin, Martin Ledinsky

In this study, Raman spectroscopy is used as a tool to determine the light-trapping capability of textured ZnO front electrodes implemented in microcrystalline silicon (mu c-Si:H) solar cells. Microcrystalline silicon films deposited on superstrates of var ...

American Institute of Physics2014

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

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

High-Quality Microcrystalline Silicon for Efficient Thin-Film Solar Cells : Insights into Plasma and Material Properties

Grégory Bugnon

This thesis investigates the link between the plasma deposition conditions and microcrystalline silicon (μc-Si:H) material quality for thin-film silicon photovoltaic applications. The role of interfaces and the μc-Si:H material quality on the device perfor ...

EPFL2013

Comparison of amorphous silicon absorber materials: Light-induced degradation and solar cell efficiency

Christophe Ballif, Grégory Bugnon, Franz-Josef Haug, Matthieu Despeisse, Michael Elias Stückelberger, Jan-Willem Alexander Schüttauf

Several amorphous silicon (a-Si:H) deposition conditions have been reported to produce films that degrade least under light soaking when incorporated into a-Si:H solar cells. However, a systematic comparison of these a-Si:H materials has never been present ...

American Institute of Physics2013

High-efficiency microcrystalline silicon single-junction solar cells

Christophe Ballif, Gaetano Parascandolo, Grégory Bugnon, Mathieu Gérard Boccard, Matthieu Despeisse, Jordi Escarre Palou, Simon Hänni

This short communication highlights our latest results towards high-efficiency microcrystalline silicon single-junction solar cells. By combining adequate cell design with high-quality material, a new world record efficiency was achieved for single-junctio ...

Wiley-Blackwell2013

Light Harvesting Schemes for High Efficiency Thin Film Silicon Solar Cells

Christophe Ballif, Mathieu Charrière, Peter Cuony, Gaetano Parascandolo, Laura Ding, Sylvain Nicolay, Grégory Bugnon, Mathieu Gérard Boccard, Matthieu Despeisse, Corsin Battaglia, Jordi Escarre Palou, Michael Elias Stückelberger, Maximilien Joseph Marie Bonnet-Eymard

In Thin Film Silicon (TF-Si) solar cells light harvesting schemes must guarantee an efficient light trapping in the thin absorber layers without decreasing the silicon layers quality and consecutively the p-i-n diodes electrical performance. TF-Si solar ce ...

Ieee2012

Geometric light trapping for high efficiency thin film silicon solar cells

Christophe Ballif, Laura Ding, Sylvain Nicolay, Grégory Bugnon, Franz-Josef Haug, Matthieu Despeisse, Corsin Battaglia, Jordi Escarre Palou

The imprinting of random square based pyramidal textures with micrometric scale at the air/glass interface of thin film silicon solar cells is presented as an efficient alternative to anti-reflective coatings to minimize reflection losses at the cell entra ...

Elsevier2012

Highly transparent ZnO bilayers by LP-MOCVD as front electrodes for thin-film micromorph silicon solar cells

Christophe Ballif, Laura Ding, Sylvain Nicolay, Grégory Bugnon, Mathieu Gérard Boccard, Matthieu Despeisse, Mustapha Benkhaira

ZnO bilayer films were deposited by a low-pressure metalorganic chemical vapor deposition technique in a single process step, by doping with boron only the nucleation stage of the growth. The resulting 2 pm thick layers are characterized by low free carrie ...

Elsevier2012

A New View of Microcrystalline Silicon: The Role of Plasma Processing in Achieving a Dense and Stable Absorber Material for Photovoltaic Applications

Christophe Ballif, Thomas Söderström, Peter Cuony, Gaetano Parascandolo, Grégory Bugnon, Matthieu Despeisse, Jakub Holovsky, Simon Hänni

To further lower production costs and increase conversion efficiency of thin-film silicon solar modules, challenges are the deposition of high-quality microcrystalline silicon (μc-Si:H) at an increased rate and on textured substrates that guarantee efficie ...

2012

LPCVD ZnO-based intermediate reflector for micromorph tandem solar cells

Christophe Ballif, Thomas Söderström, Laura Ding, Sylvain Nicolay, Grégory Bugnon, Matthieu Despeisse

The use of zinc oxide (ZnO) based intermediate reflector (ZIR) in micromorph solar cells using low pressure chemical vapor deposition (LPCVD) was investigated. The influences of deposition temperature and dopant gas concentration on grain size and lateral ...

2011

Microcrystalline and micromorph device improvements through combined plasma and material characterization techniques

Christophe Ballif, Benjamin Strahm, Andrea Feltrin, Gaetano Parascandolo, Grégory Bugnon

Hydrogenated microcrystalline silicon (μc-Si:H) growth by very high frequency plasma-enhanced chemical vapor deposition (VHF-PECVD) is studied in an industrial-type parallel plate KAI reactor. Combined plasma and material characterization techniques allow ...

Elsevier B.V Amsterdam2011

Resistive interlayer for improved performance of thin film silicon solar cells on highly textured substrate

Christophe Ballif, Andrea Feltrin, Peter Cuony, Grégory Bugnon, Adrian Billet, Matthieu Despeisse, Michael Elias Stückelberger

The deposition of thin-film silicon solar cells on highly textured substrates results in improved light trapping in the cell. However, the growth of silicon layers on rough substrates can often lead to undesired current drains, degrading performance and re ...

AIP American Institute of Physics2010