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

Olivier Sauter, Ambrogio Fasoli, Yiming Li, Basil Duval, Martinus Gijs, Duccio Testa, Jonathan Graves, Patrick Blanchard, Federico Alberto Alfredo Felici, Alessandro Pau

For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des. 82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D-T mixtures si ...

IOP Publishing Ltd2019

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

Christophe Ballif, Franz-Josef Haug, Karin Söderström

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

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, Franz-Josef Haug, Karin Söderström, 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, Franz-Josef Haug, Corsin Battaglia, Karin Söderström, 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, Toralf Scharf, Karin Söderström, Vincent Paeder, 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