Publications de Christophe Ballif

Chattez avec Graph Search

Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.

AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.

Nanoindentation and nanoscratching of an indium phosphide (InP) semiconductor surface was investigated via contact mechanics. Plastic deformation in InP is known to be caused by the nucleation, propagation, and multiplication of dislocations. Using selective electrochemical dissolution, which reveals dislocations at the semiconductor surface, the load needed to create the first dislocations in indentation and scratching can be determined. The experimental results showed that the load threshold to generate t

The stability in humid environment of low pressure chemical vapor deposited boron doped zinc oxide (LPCVD ZnO:B) used as transparent conductive oxide in thin film silicon solar cells is investigated. Damp heat treatment (exposition to humid and hot atmosph ...

We investigated Si nanowires (SiNWs) fabricated by wet etching and chemical vapor deposition (CVD), and core-shell structures, formed by depositing silicon layers around the SiNWs, with respect to their crystallinity, the doping level, and the influence of surface passivation on carrier lifetime. The effects expected to be critical to improve the performance of nanowire-based solar cells are discussed. ©2010 IEEE.

Partial shading can trigger permanent damage in photovoltaic modules because the illuminated solar cells drive the shaded cells into reverse bias. Under reverse bias conditions, perovskite solar cells have been shown to degrade quickly due to processes tha ...

Whether illumination influences the ion conductivity in lead-halide perovskite solar cells containing iodide halides has been an ongoing debate. Experiments to elucidate the presence of a photoconductive effect require special devices or measurement techni ...

In this study, Raman spectroscopy is used as a tool to determine the light-trapping capability of textured ZnO front electrodes implemented in microcrystalline silicon (mu c-Si:H) solar cells. Microcrystalline silicon films deposited on superstrates of var ...

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 ...

Amorphous/crystalline silicon interfaces feature considerably larger valence than conduction band offsets. In this article, we analyze the impact of such band offset asymmetry on the performance of silicon heterojunction solar cells. To this end, we use si ...

Hydrogenated microcrystalline silicon growth by very high frequency plasma-enhanced chemical vapor deposition is investigated in an industrial-type parallel plate R&D KAI (TM) reactor to study the influence of pressure and silane depletion on material qual ...

Extensive knowledge of the dependence of solar cell and module performance on temperature and irradiance is essential for their optimal application in the field. Here we study such dependencies in the most common high-efficiency silicon solar cell architec ...

To further increase the efficiency of multijunction thin-film silicon (TF-Si) solar cells, it is crucial for the front electrode to have a good transparency and conduction, to provide efficient light trapping for each subcell, and to ensure a suitable morp ...

Decarbonizing mobility and integrating more renewable sources in electricity production are necessary levers to meet the climate targets. Coupling electric vehicle (EV) charging with photovoltaic (PV) electricity generation could help to provide clean elec ...

Because of building skin integration with restricted or reduced rear-side ventilation, elevated operating temperatures are expected in building-integrated photovoltaics (BIPV) modules and systems, which may impact their long performance and reliability. Th ...

We study the respective influence of haze and free carrier absorption (FCA) of transparent front electrodes on the photogenerated current of micromorph thin film silicon solar cells. To decouple the haze and FCA we develop bi-layer front electrodes: a flat indium tin oxide layer assures conduction and allows us to tune FCA while the haze is adjusted by varying the thickness of a highly transparent rough ZnO layer. We show how a minimum amount of FCA leads only to a few percents absorption for a single light

Synchrotron micro- and nanoprobe beamlines have demonstrated great potential to advance photovoltaic devices. Most importantly, their small X-ray spot size has enabled the direct correlation of electrical performance with elemental composition at subgrain ...

Appropriate encapsulation schemes are essential in protecting the active components of the photovoltaic (PV) module against weathering and to ensure long term reliability. For crystalline cells, Poly (ethylene-co-vinyl acetate) (EVA) is the most commonly u ...

In recent years, the importance of electric mobility has increased in response to climate change. The fast-growing deployment of electric vehicles (EVs) worldwide is expected to decrease transportation-related emissions, facilitate the integration of renew ...

In silicon heterojunction solar cells, thin amorphous silicon layers passivate the crystalline silicon wafer surfaces. By using in situ diagnostics during plasma-enhanced chemical vapor deposition (PECVD), the authors report how the passivation quality of such layers directly relate to the plasma conditions. Good interface passivation is obtained from highly depleted silane plasmas. Based upon this finding, layers deposited in a large-area very high frequency (40.68 MHz) PECVD reactor were optimized for het

High penetration of photovoltaic (PV) electricity could affect the stability of the low-voltage grid due to over-voltage and transformer overloading at times of peak production. Residential battery storage can smooth out those peaks and hence contribute to ...

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 ...

Christophe Ballif

Chattez avec Graph Search

Analysis of onset of dislocation nucleation during nanoindentation and nanoscratching of InP

Humid environment stability of LPCVD ZnO: B used as transparent electrodes in thin film silicon solar cells

Structural, optical, and electrical properties of silicon nanowires for solar cells

Instability of p-i-n perovskite solar cells under reverse bias

Assessing the Influence of Illumination on Ion Conductivity in Perovskite Solar Cells

Light trapping in thin-film solar cells measured by Raman spectroscopy

Improved amorphous/crystalline silicon interface passivation by hydrogen plasma treatment

Asymmetric band offsets in silicon heterojunction solar cells: Impact on device performance

Influence of pressure and silane depletion on microcrystalline silicon material quality and solar cell performance

The impact of silicon solar cell architecture and cell interconnection on energy yield in hot & sunny climates

Highly transparent modulated surface textured front electrodes for high-efficiency multijunction thin-film silicon solar cells

A Spatiotemporal analysis of photovoltaic electricity storage potential in electric vehicles

Operating Temperatures and Diurnal Temperature Variations of Modules Installed in Open-Rack and Typical BIPV Configurations

Unlinking absorption and haze in thin film silicon solar cells front electrodes

Effects of X-rays on Perovskite Solar Cells

Insights into the encapsulation process of photovoltaic modules: GC-MS analysis on the curing step of Poly (ethylene-co-vinyl acetate) (EVA) encapsulant

Deep reinforcement learning control of electric vehicle charging in the presence of photovoltaic generation

The silane depletion fraction as an indicator for the amorphous/crystalline silicon interface passivation quality

Control algorithm for a residential photovoltaic system with storage

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