MANAGEMENT OF SILVER LAYER MICROSTRUCTURE AND PROPERTIES
Sputtered silver thin layers
Ramiro Zapata (PhD student), Hervé Montigaud, Matteo Balestrieri and Iryna Gozhyk in collaboration with R. Lazzari (INSP)
Low-emissivity glasses can be integrated into insulating glazing to increase their insulating performance. To obtain a low-E glass, a stack of thin layers, including at least one thin metal layer (typically silver), is deposited on the glass surface. Achieving the highest possible electrical conductivity is the key to obtain efficient infrared light reflection combined with high optical transparency. Producing 10 nm-thick silver layers with bulk-like conductivity is a technical challenge, due to the natural tendency of noble metals to dewet on oxide layers and to form polycristalline films. In our lab, we investigate not only the process parameters but also the stack structures that have an impact on the silver growth (surface mobility, nucleation, stress…) and the final film microstructure.
Nanostructuring metal layers
Marie-Caroline Solignac (PhD student), Iryna Gozhyk, Hervé Montigaud and Matteo Balestrieri in collaboration with K. Vynck and P. Lalanne (IOGS)
It is well known that the plasmonic properties of noble metals can be used to tune the color of objects. This research axis investigates how the layer properties at the nanoscale influence the macroscopic aspect of the system. From the process point of view, we study the effect of the deposition parameters and layer stack on the particle size, shape, distribution and crystalline texture. We use both in-situ and ex-situ caracterization tools to access these properties. This topicis closely related to our research activities in advanced optics of nanostructured media. In collaboration with the IOGS institute in Bordeaux, we develop sophisticated and effective models to predict the macroscopic properties of these systems starting and we try to identify the significant experimental data.
STUDY OF SPUTTERED LAYERS AND STACKS
Thin films of metals, oxydes, and nitrides
The deposition of layer stacks on the glass surface is the basis of functionalized glazing, and sputtering is the most used technique in the industry. The materials of interest are numerous and the layer properties depend on the process parameters, the nature of seed- and under-layers …. Among the different axes explored at SVI, we can list the following studies:
- The interactions of a thin metal layer (Ti, NiCr) during its deposition by magnetron sputtering with ZnO seed layer.
- The growth mode of sputtered Ag layer depending on the seed layer (SiO2, ZnO, AZO) or the operating conditions (Pressure, gas mixture, power, geometry).
- The links between the operating conditions during sputtering in DC mode and the morphology of amorphous silicon nitride (SiNx) layers and the consequences on its barrier behavior.
- Selective and passivating transparent conductive layers for back contact in CuInGaSe2 solar cell technology (ANR Pastel).
PHOTOCATALYSIS
TiO2 photocatalysis
Adrien Girault (PhD student), Matteo Balestrieri, Hervé Montigaud and Iryna Gozhyk in collaboration with P. Gilliot and M. Gallart (IPCMS)
Several commercial self-cleaning windows are functionalized by a thin film stack including a final TiO2 film. The succes of this material is related to its excellent photocatalytic activity and super-hydrophilicity, but also to its excellent stability. In fact, a hydrophilic active surface is essential to assure self-cleaning properties based on the degradation of organic dirt accumulating at the surface of windows. Upon exposure to water (typically rain), the dirt is washed away. The excellent stability of TiO2 ensures functionality on the long term.
In collaboration with the IPCMS lab in Strasbourg, we investigate the links between the microstructure of ultrathin TiO2 films, the carrier dynamics and the photocatalytic activity.
POST-TREATMENT
Impact of post-treatment on film properties
We study different kind of post-deposition treatment such as thermal and laser heating, ion bombardment etc. and the effect on the material properties.
