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Christophe Ballif

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Related publications (443)

Influence of the ZnO buffer layer on the guided mode structure in Si/ZnO/Ag multilayers

Christophe Ballif, Thomas Söderström, Vanessa Terrazzoni-Daudrix, Franz-Josef Haug

We present a study of the optical mode structure in metal-dielectric multilayer structures that represent amorphous silicon thin film solar cells with metallic back contact. Knowledge of the modal structure represents a first step toward describing absorpt ...

2009

Thin film silicon solar cells in a semi-transparent micro-structured metal substrate configuration

Christophe Ballif, Sylvie Faÿ, Julien Claude Bailat

We present our work on the combination of thin film silicon solar cells and a commercial window shading device (MicroShadeTM, PhotoSolar) into a novel, glass integrated photovoltaic product for building integration. The development of amorphous silicon sol ...

2009

Development of micromorph tandem soalr cells on flexible low cost plastic substrates

Christophe Ballif, Martin Python, Thomas Söderström, Xavier Niquille, Vanessa Terrazzoni-Daudrix, Franz-Josef Haug

We report on the development of fully flexible microcrystalline and micromorph tandem solar cells directly on low-cost substrates like poly-ethylen-terephtalate (PET) and poly-ethylen-naphtalate (PEN). The cells are deposited in nip or nip/nip configuratio ...

2009

MICROCRYSTALLINE SILICON SOLAR CELLS: EFFECT OF SUBSTRATE TEMPERATURE ON CRACKS

Christophe Ballif, Martin Python

Single junction microcrystalline silicon solar cells presently reach confirmed efficiencies up to 10.1%. Further improvement on device quality is now necessary to continuously increase the electrical performances of the solar cells. Zones of porous materia ...

2009

Asymmetric intermediate reflector for tandem micromorph thin film silicon solar cells

Christophe Ballif, Thomas Söderström, Xavier Niquille, Vanessa Terrazzoni-Daudrix, Franz-Josef Haug

The micromorph solar cell (stack of amorphous and microcrystalline cells) concept is the key for achieving high efficiency stabilized thin film silicon solar cells. We introduce a device structure that allows a better control of the light in-coupling into ...

AIP American Institute of Physics2009

LATEST DEVELOPMENTS ON MICROMORPH TANDEM CELLS AT IMT

Christophe Ballif, Andrea Feltrin, Gaetano Parascandolo, Grégory Bugnon, Matthieu Despeisse

The latest developments on micromorph tandem cells in small area laboratory and large area industrial PE-CVD systems are reviewed. We report on a 13.3% initial efficiency micromorph tandem cell deposited in our small area system. The development of an in-s ...

2009

Influence of the substrate geometrical parameters on microcrystalline silicon growth for thin-film solar cells

Christophe Ballif, Martin Python, Omid Madani Ghahfarokhi

The effect of substrate morphology on the growth and electrical properties of single-junction microcrystalline silicon cells is investigated. A large variety of V-shaped and U-shaped substrates are characterized by scanning electron microscopy (SEM) and th ...

2009

Silane depletion dependent ion bombardment and material quality of microcrystalline silicon deposited by VHF-PECVD

Christophe Ballif, Andrea Feltrin, Grégory Bugnon, Julien Claude Bailat

Microcrystalline silicon is a composite material embedding silicon nanocrystals in an amorphous matrix [1]. It has attracted much research efforts in the photovoltaic domain [2], because of its potential for integration in a tandem cell concept as bottom c ...

2009

LPCVD GROWTH OF ZNO FOR SOLAR CELL APPLICATIONS

Christophe Ballif, Sylvie Faÿ, Sylvain Nicolay

A growth model for the low pressure chemical vapor deposition (LPCVD) of polycrystalline ZnO thin films is proposed. This model is based on experimental observations of the surface morphology and crystallographic orientations of the layers at different thi ...

2009

Infrared laser-based monitoring of the silane dissociation during deposition of silicon thin films

Christophe Ballif, Andrea Feltrin

The silane dissociation efficiency, or depletion fraction, is an important plasma parameter by means of which the film growth rate and the amorphous-to-microcrystalline silicon transition regime can be monitored in situ. In this letter we implement a homeb ...

AIP American Institute of Physics2009

Limiting factors in the fabrication of microcrystalline silicon solar cells and microcrystalline/amorphous (‘micromorph’) tandems

Christophe Ballif, Arvind Shah, Martin Python, Andrea Feltrin, Grégory Bugnon

This contribution presents the status of amorphous and microcrystalline silicon solar cells on glass, and discusses some material/fabrication factors that presently limit their conversion efficiency. Particular attention is focused on recent results and de ...

2009

Study of the microstructure transition width from amorphous to microcrystalline silicon as a function of the input silane concentration

Christophe Ballif, Christoph Hollenstein, Benjamin Strahm, Andrea Feltrin, Grégory Bugnon

Amorphous and microcrystalline silicon have been proven to be very interesting for low cost thin film photovoltaic devices. Usually these two materials are deposited using the same large area plasma-enhanced chemical vapor deposition reactors from silane a ...

2009

Optical emission spectroscopy to diagnose powder formation in SiH4-H2 discharges

Christophe Ballif, Benjamin Strahm, Andrea Feltrin

Silane and hydrogen discharges are widely used for the deposition of silicon thin film solar cells in large area plasmaenhanced chemical vapor deposition reactors. In the case of microcrystalline silicon thin film solar cells, it is of crucial importance t ...

2009

TEM characterization of textured silicon heterojunction solar cells

Christophe Ballif, Aïcha Hessler-Wyser, Christian Monachon

Increasing the efficiency of crystalline silicon (c-Si) solar cells requires the reduction of both bulk and interface recombination. Even if bulk recombination is almost suppressed, the symmetry of the crystal lattice is disturbed at the surface and hence, ...

Springer2008

Effects of edge defects induced by multi-wire sawing on the wafer strength

Christophe Ballif, Mathijs Pieter van der Meer, Adrien Bidiville, Fanny Alexia Jeanneret

The focus of the photovoltaic industry is a continuous reduction of the cost of solar energy. Lowering the wafer thickness during the processing by means of multi-wire slurry saw technology is one of the key issue to reduce these costs. However, reducing t ...

2008

Influence of ion bombardment on microcrystalline silicon material quality and solar cell performances

Christophe Ballif, Fanny Sculati-Meillaud, Andrea Feltrin, Grégory Bugnon, Julien Claude Bailat

Microcrystalline hydrogenated silicon growth with VHF-PECVD was examined in an industrial type parallel plate KAITM reactor. The influence of pressure on material quality was studied in single junction solar cells. Solar cells with their intrinsic layer pr ...

2008

Low power high growth rate deposition of microcrystalline silicon

Christophe Ballif, Andrea Feltrin, Grégory Bugnon, Julien Claude Bailat

Microcrystalline growth regimes and solar cells obtained in different pressure and silane depletion conditions are studied in a large area KAI-S plasma reactor. The microcrystalline material quality is systematically investigated by Fourier Transform Photo ...

2008

Plasma Modelling and Diagnostics for the Prediction of Structural Changes in Silicon Thin Film Deposition Plasma Modelling and Diagnostics for the Prediction of Structural Changes in Silicon Thin Film Deposition

Christophe Ballif, Andrea Feltrin, Grégory Bugnon

In the present work, we apply a 2D self consistent model of SiH4/H2 discharges in order to investigate the transition from microcrystalline to amorphous silicon growth. The model is used to examine the relative importance of ions and atomic hydrogen in the ...

2008

Micromorph tandem solar cells grown at high rate with in-situ intermediate reflector in industrial KAI PECVD reactors

Christophe Ballif, Andrea Feltrin, Grégory Bugnon, Adrian Billet, Julien Claude Bailat

We report on the latest results of tandem micromorph (a-Si:H/μc-Si:H) silicon solar cells fabricated in commercial Oerlikon Solar KAI-S and KAI-M PECVD reactors. First developments of in-situ silicon oxide based intermediate reflector (SOIR) in KAI reactor ...

2008

Textured silicon heterojunction solar cells with over 700mV open-circuit voltage studied by transmission electron microscopy

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

In this article, we report on the use of transmission electron microscopy (TEM) for the fabrication of high-performance textured amorphous/crystalline silicon (a-Si:H/c-Si) heterojunction (HJ) solar cells. Whereas classical thin-film characterization techn ...

2008

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