Publications de Benjamin Strahm

Interdigitated back contact silicon heterojunction solar cells featuring an interband tunnel junction enabling simplified processing

Christophe Ballif, Quentin Thomas Jeangros, Antoine Descoeudres, Antonin Faes, Gabriel Christmann, Jonas Geissbühler, Matthieu Despeisse, Bertrand Yves Paul Paviet-Salomon, Stefaan De Wolf, Nicolas Badel

This paper reports on the development of an innovative back-contacted crystalline silicon solar cell with passivating contacts featuring an interband tunnel junction at its electron-collecting contacts. In this novel architecture, named "tunnel-IBC", both ...

2018

Improved amorphous/crystalline silicon interface passivation by hydrogen plasma treatment

Christophe Ballif, Antoine Descoeudres, Stefaan De Wolf, Loris Barraud, Benjamin Strahm, Jakub Holovsky, Johannes Peter Seif, Bénédicte Demaurex

Silicon heterojunction solar cells have high open-circuit voltages thanks to excellent passivation of the wafer surfaces by thin intrinsic amorphous silicon (a-Si:H) layers deposited by plasma-enhanced chemical vapor deposition. We show a dramatic improvem ...

2011

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

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

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

Input silane concentration effect on the a-Si:H to uc-Si:H transition width

Christophe Ballif, Christoph Hollenstein, Grégory Bugnon, Andrea Feltrin, Benjamin Strahm, Fanny Sculati-Meillaud

In this work the microstructure transition width from amorphous to microcrystalline silicon is discussed. It is shown that the width of the transition depends on the input silane concentration level and indirectly on the silane depletion level. The higher ...

2010

Powder formation in SiH[sub 4]–H[sub 2] discharge in large area capacitively coupled reactors: A study of the combined effect of interelectrode distance and pressure

Christoph Hollenstein, Benjamin Strahm

One of the main challenges for silicon thin film deposition for solar cell applications is to achieve high rate deposition in order to reduce the manufacturing costs. However, when silane and hydrogen are used as precursor gas in parallel plate plasma-enha ...

American Institute of Physics2010

Laser applications in thin-film photovoltaics

Christophe Ballif, Andrea Feltrin, Benjamin Strahm

We review laser applications in thin-film photovoltaics (thin-film Si, CdTe, and Cu(In,Ga)Se2 solar cells). Lasers are applied in this growing field to manufacture modules, to monitor Si deposition processes, and to characterize opto-electrical properties ...

Springer Verlag2009

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

Christophe Ballif, Andrea Feltrin, Benjamin Strahm

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

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

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

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

Laser-based plasma diagnostics for PECVD of silicon thin films

Christophe Ballif, Andrea Feltrin, Benjamin Strahm

We present two laser systems to monitor plasma conditions in a plasma-enhanced chemical vapor deposition chamber. The first optical system is a high-resolution quantum cascade laser-based infrared absorption spectrometer designed to measure the input silan ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2009

Non-intrusive plasma diagnostics for the deposition of large area thin film silicon

Christoph Hollenstein, Alan Howling, Benjamin Strahm

Plasma diagnostics for large area, industrial RF parallel-plate reactors can be useful for process optimization and monitoring, provided that their implementation is practical and non-intrusive. For instance, Fourier transform infrared (FTIR) absorption sp ...

Elsevier2009