Publications by Christophe Ballif

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CMOS-based Amorphous Silicon Microchannel Plate (CAMCP) detectors are devices built on and read-out by a multi-channel CMOS tile, using a PLANACON photocathode and a hexagonal grid of high aspect ratio micro-channels. Metascintillators are combinatory scintillators comprising more than one type of material, exploiting the electron leakage from a dense scintillator to a fast one. The two structures were simulated together using GATE. The scintillator had dimensions of 24×9.6×7.7 mm3, made of 22 slabs of LYSO

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. ...

Light-induced degradation (LID) of crystalline silicon (c-Si) surfaces passivated with hydrogenated amorphous silicon (a-Si:H) is investigated. The initial passivation decays on polished c-Si(100) surfaces on a time scale much faster than usually associated with bulk a-Si:H LID. This phenomenon is absent for the a-Si:H/c-Si(111) interface. We attribute these differences to the allowed reconstructions on the respective surfaces. This may point to a link between the presence of so-called "fast" states and (in

Several amorphous silicon (a-Si:H) deposition conditions have been reported to produce films that degrade least under light soaking when incorporated into a-Si:H solar cells. However, a systematic comparison of these a-Si:H materials has never been present ...

A reliable and aesthetically pleasing lightweight (LW) photovoltaic (PV) module for building integration is expected to develop a growing interest in the consumer market. However, its application is still limited by old buildings that are not structurally ...

The latest developments on micromorph tandem cells in small area laboratory and large area industrial PE-CVD systems are reviewed. We report on a 13.3% initial efficiency micromorph tandem cell deposited in our small area system. The development of an in-s ...

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 ...

The recycling or re-use of failed c-Si PV modules could be a significant concern in the near future. The existing approaches for cell recovery can be improved both environmentally and economically friendly. Here we propose a novel double encapsulation module with an optical coupler (DEMOC) module design for convenient c-Si cell recovery. In this paper, the concept of DEMOC is illustrated. We successfully determine the materials and lamination recipes for single-cell re-usable mini-modules. The optical refle

We investigate the efficiency potential of organic-inorganic halide perovskite/crystalline silicon tandem solar cells, a new class of photovoltaic devices targeting long-term cost reductions by ultrahigh conversion efficiencies. Methyl ammonium lead triiod ...

Hydrogenated amorphous silicon betavoltaic devices are studied both by simulation and experimentally. Devices exhibiting a power density of 0.1 μW/cm2 upon Tritium exposure were fabricated. However, a significant degradation of the performance is taking pl ...

Microchannel plates (MCP) based on hydrogenated amorphous silicon (a-Si:H) were recently introduced to overcome some of the limitations of crystalline silicon and glass MCP. The typical thickness of a-Si:H based MCPs (AMCP) ranges between 80 and 100 μm and the micromachining of the channels is realized by deep reactive ion etching (DRIE). Advantages and issues regarding the fabrication process are presented and discussed. Electron amplification is demonstrated and analyzed using Electron Beam Induced Curren

Combining market-proven silicon solar cell technology with an efficient wide band gap top cell into a tandem device is an attractive approach to reduce the cost of photovoltaic systems. For this, perovskite solar cells are promising high-efficiency top cel ...

Carrier collection in silicon heterojunction (SHJ) solar cells is usually achieved by doped amorphous silicon layers of a few nanometers, deposited at opposite sides of the crystalline silicon wafer. These layers are often defect-rich, resulting in modest ...

We report on the fabrication of back-contacted silicon heterojunction solar cells with conversion efficiencies above 21%. Our process technology relies solely on simple and size-scalable patterning methods, with no high-temperature steps. Using in situ sha ...

Micro-Raman spectroscopy provides laterally resolved microstructural information for a broad range of materials. In this Letter, we apply this technique to tri-iodide (CH3NH3PbI3), tribromide (CH3NH3PbBr3), and mixed iodide-bromide (CH3NH3PbI3-xBrx) organi ...

Nanopatterning has gained tremendous importance in the field of photovoltaics, as absorption of sunlight in solar cells can be enhanced drastically by proper engineering of photonic nanostructures1– 8. However, despite intensive efforts, neither the ideal surface morphology nor the ideal scattering characteristics foroptimumlight trapping have been identified. Experimentally, a method capable of implementing arbitrarily designed surface morphologies directly into functional devices is desirable. Here, we es

We evaluate the potential of three-dimensional (3D) thin-film silicon solar cells in the superstrate configuration deposited on hexagonally ordered arrays of ZnO nanocolumns (NCs). These nanostructures are prepared by hydrothermal growth, which is an effec ...

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 ...

The focus of the photovoltaic industry is a continuous reduction of the cost of solar energy. Lowering the wafer thickness during the processing by means of multi-wire slurry saw technology is one of the key issue to reduce these costs. However, reducing t ...

Christophe Ballif

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Simulation of CMOS-based Amorphous Silicon Microchannel Plate Detectors for Metascintillators

Geometrical Impact on Guided Mode Excitation in Solar Cells

Very fast light-induced degradation of a-Si:H/c-Si(100) interfaces

Comparison of amorphous silicon absorber materials: Light-induced degradation and solar cell efficiency

Novel Lightweight PV Modules Based on Polymeric Honeycomb for Building Integration

LATEST DEVELOPMENTS ON MICROMORPH TANDEM CELLS AT IMT

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

Re-Use of c-Si Solar Cells from Failed PV Modules

Re-Use of c-Si Solar Cells from Failed PV Modules

Organic-Inorganic Halide Perovskites: Perspectives for Silicon-Based Tandem Solar Cells

Amorphous silicon based betavoltaic devices

Amorphous silicon-based microchannel plates

Efficient Near-Infrared-Transparent Perovskite Solar Cells Enabling Direct Comparison of 4-Terminal and Monolithic Perovskite/Silicon Tandem Cells

Strategies for Doped Nanocrystalline Silicon Integration in Silicon Heterojunction Solar Cells

Back-Contacted Silicon Heterojunction Solar Cells With Efficiency >21%

Raman Spectroscopy of Organic-Inorganic Halide Perovskites

Nanomoulding of transparent zinc oxide electrodes for efficient light trapping in solar cells

Three-dimensional amorphous silicon solar cells on periodically ordered ZnO nanocolumns

Research and developments in thin film silicon photovoltaics

Effects of edge defects induced by multi-wire sawing on the wafer strength