Publications by Thomas Söderström

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 silicon solar cells: effect of substrate temperature on cracks and their role in post-oxidation

Christophe Ballif, Martin Python, Thomas Söderström

Microcrystalline silicon (mc-Si:H) cells can reach efficiencies up to typically 10% and are usually incorporated in tandem micromorph devices. When cells are grown on rough substrates, ‘‘cracks’’ can appear in the mc-Si:H layers. Previous works have demons ...

2010

ZnO Transparent conductive oxide for thin film silicon solar cells

Christophe Ballif, Sylvie Faÿ, Thomas Söderström, Andrea Feltrin, Peter Cuony, Sylvain Nicolay, Grégory Bugnon, Franz-Josef Haug, Mathieu Gérard Boccard, Matthieu Despeisse

There is general agreement that the future production of electric energy has to be renewable and sustainable in the long term. Photovoltaic (PV) is booming with more than 7GW produced in 2008 and will therefore play an important role in the future electric ...

Spie-Int Soc Optical Engineering, Po Box 10, Bellingham, Wa 98227-0010 Usa2010

Flexible micromorph tandem a-Si/µc-Si solar cells

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

The deposition of a stack of amorphous (a-Si:H) and microcrystalline (µc- Si:H) tandem thin film silicon solar cells (micromorph) requires at least twice the time used for a single junction a-Si:H cell. However, micromorph devices have a higher potential e ...

2010

Research and developments in thin film silicon photovoltaics

Christophe Ballif, Sylvie Faÿ, Martin Python, Thomas Söderström, Andrea Feltrin, Gaetano Parascandolo, Grégory Bugnon, Franz-Josef Haug, Matthieu Despeisse

The increasing demand for photovoltaic devices and the associated crystalline silicon feedstock demand scenario have led in the past years to the fast growth of the thin film silicon industry. The high potential for cost reduction and the suitability for b ...

2009

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

FINAL RESULTS OF THE EUROPEAN PROJECT FLEXCELLENCE ROLL TO ROLL TECHNOLOGY FOR THE PRODUCTION OF HIGH EFFICIENCY LOW COST THIN FILM SOLAR CELLS

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

This paper reports on the final main results of the Flexcellence project. The project was running for 3 years and its goal was the development of equipments and processes for cost-effective roll-to-roll production of high-efficiency flexible thin-film sili ...

2009

Light trapping effects in thin film silicon solar cells

Christophe Ballif, Thomas Söderström, Franz-Josef Haug

We present advanced light trapping concepts for thin film silicon solar cells. When an amorphous and a microcrystalline absorber layers are combined into a micromorph tandem cell, light trapping becomes a challenge because it should combine the spectral re ...

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

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

Fabrication and characterisation of polymer based solar cells

Thomas Söderström

Tandem solar cells, in which two individual cells are stacked on top of each other, offer the potential to increase the efficiency significantly compared to a single cell on the same area. To reach maximum efficiency, each cell in the stack must have a dis ...

2008