Publications by Karin Söderström

Runaway electron beam stability and decay in COMPASS

Karin Söderström, Joan Decker, Gergely Papp

This paper presents two scenarios used for generation of a runaway electron (RE) beam in the COMPASS tokamak with a focus on the decay phase and control of the beam. The first scenario consists of massive gas injection of argon into the current ramp-up pha ...

IOP Publishing Ltd2019

Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall

Patrick Blanchard, Basil Duval, Ambrogio Fasoli, Richard Pitts, Olivier Sauter, Henri Weisen, Martinus Gijs, Partha Dutta, Marco Wischmeier, Jan Horacek, Vlad Trifa, Yann Camenen, Jonathan Graves, Francesca Maria Poli, Ricardo Lima, Duccio Testa, Emiliano Fable, Karin Söderström, Sun Hee Kim, Mikhail Maslov, Javier García Hernández, Soo-Jin Moon, Federico Alberto Alfredo Felici, José Pedro Rebelo Ferreira Marques, Julio Rodriguez, Pedro Camilo de Oliveira e Silva, Daniel Scott Alessi, Daniele Brunetti, Jonnathan Cesar Hidalgo Acosta, Ana Francisca Leal Silva Soares, Dalziel Joseph Wilson, Antoine Pierre Emmanuel Alexis Merle, Federico Nespoli, Alberto Hernando de Castro, Anna Teplukhina, Leonardo Pigatto, Hamish William Patten, Alberto Mariani, Bruno Emanuel Ferreira De Sousa Correia, , , , , , , , , , , , , , , ,

Absorption Enhancement in Solar Cells With Periodic Interface Textures of Asymmetric Shape

Christophe Ballif, Karin Söderström, Franz-Josef Haug

We investigate light scattering interface textures for solar cells with the intention to obtain a more fundamental understanding of the absorption enhancement. Therefore, we study simplified structures with the periodic interface texture of sinusoidal and ...

Ieee-Inst Electrical Electronics Engineers Inc2015

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

Coupling light into thin silicon layers for high-efficiency solar cells

Karin Söderström

Thin-film solar cells based on amorphous and microcrystalline silicon require thin photoactive layers to ensure a satisfactory collection of the photogenerated carriers. The small thickness is advantageous in terms of raw material consumption and industria ...

EPFL2013

Geometrical Impact on Guided Mode Excitation in Solar Cells

Christophe Ballif, Hans Peter Herzig, Karin Söderström, Franz-Josef Haug, Ali Naqavi

We investigate the influence of patterned metallic back reflector on absorption in thinfilm silicon photovoltaics. The impact of symmetry, periodicity, and angle of incidence of light is discussed by simulation and experiment. ...

2012

Light trapping in solar cells: can periodic beat random?

Christophe Ballif, Marco Cantoni, Mathieu Charrière, Karin Söderström, Duncan Thomas Lindsay Alexander, Franz-Josef Haug, Mathieu Gérard Boccard, Matthieu Despeisse, Corsin Battaglia, Jordi Escarre Palou

Theory predicts that periodic photonic nanostructures should outperform their random counterparts in trapping light in solar cells. However, the current certified world-record conversion efficiency for amorphous silicon thin-film solar cells, which strongl ...

2012

Resonances and absorption enhancement in thin film silicon solar cells with periodic interface texture

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

We study absorption enhancement by light scattering at periodically textured interfaces in thin film silicon solar cells. We show that the periodicity establishes resonant coupling to propagating waveguide modes. Ideally, such modes propagate in the high i ...

American Institute of Physics2011

High fidelity transfer of nanometric random textures by UV embossing for thin film solar cells applications

Christophe Ballif, Karin Söderström, Franz-Josef Haug, Corsin Battaglia, Jordi Escarre Palou

We investigate the transfer of random nanostructures commonly used in thin film silicon solar cells onto inexpensive substrates, such as glass or flexible polyethylene sheets. Morphological and optical analyses of masters and replicas show the successful t ...

Elsevier2011

Understanding of photocurrent enhancement in real thin film solar cells: towards optimal onedimensional gratings

Christophe Ballif, Hans Peter Herzig, Karin Söderström, Vincent Paeder, Toralf Scharf, Ali Naqavi

Despite the progress in the engineering of structures to enhance photocurrent in thin film solar cells, there are few comprehensive studies which provide general and intuitive insight into the problem of light trapping. Also, lack of theoretical propositio ...

Optical Society of America2011

UV-nano-imprint lithography technique for the replication of back reflectors for n-i-p thin film silicon solar cells

Christophe Ballif, Karin Söderström, Franz-Josef Haug, Jordi Escarre Palou

Texturing of interfaces in thin film silicon solar cells is essential to enhance the produced photocurrent and thus the efficiencies.AUVnano-imprint-lithography (UV-NIL) replication processwas developed to prepare substrates with textures that are suitable ...

2010

An RCWA Analysis of Solar Cell Back Reflectors: Comparison between Modelling and Experiment

Christophe Ballif, Hans Peter Herzig, Karin Söderström, Vincent Paeder, Toralf Scharf, Franz-Josef Haug, Ali Naqavi

We present a comparison between spectrally-resolved reflection measurements of gratings and theoretical predictions from RCWA approach. Diffraction intensities vary significantly with polarization, and surface plasmon absorption is observed around the onse ...

2010

NANO-IMPRINT TECHNIQUE FOR BACK REFLECTOR IN HIGH EFFICIENCY N-I-P THIN FILM SILICON SOLAR CELLS

Christophe Ballif, Céline Pahud, Karin Söderström, Franz-Josef Haug, Jordi Escarre Palou, Rémi Biron

In this contribution, the replication of nano-textures enhancing the short circuit current of thin film silicon solar cells onto low cost substrates (glass or PolyEthylene Naphtalate (PEN)) is studied. Optical and morphological analysis is performed to ass ...

2010