Silver nanowire (AgNW) networks are emerging as one of the most promising alternatives to indium tin oxide (ITO) for transparent electrodes in flexible electronic devices. They can be used in a variety of optoelectronic applications such as solar cells, touch panels and organic light-emitting diodes. Recently they have also proven to be very efficient when used as transparent heaters (THs). In addition to the study of AgNW networks acting as THs in regular use, i.e. at low voltage and moderate temperature, their stability and physical behavior at higher voltages and for longer durations should be studied in view of their integration into real devices. The properties of AgNW networks deposited by spray coating on glass or flexible transparent substrates are thoroughly studied via in situ measurements. The AgNW networks' behavior at different voltages for different durations and under different atmospheric conditions, both in air and under vacuum, has been examined. At low voltage, a reversible electrical response is observed while irreversibility and even failure are observed at higher voltages. In order to gain a deeper insight into the behavior of AgNW networks used as THs, simple but realistic physical models are proposed and are found to be in fair agreement with the experimental data. Finally, as the stability of AgNW networks is a key issue, we demonstrate that coating AgNW networks with a very thin layer of TiO using atomic layer deposition (ALD) improves the material's resistance against electrical and thermal instabilities without altering optical transmittance. We show that the critical annealing temperature associated to network breakdown increases from 270 °C for the as-deposited AgNW networks to 420 °C for AgNW networks coated with TiO. Similarly, the electrical failure which occurs at 7 V for the as-deposited networks increases to 13 V for TiO-coated networks. TiO is also proved to stabilize AgNW networks during long duration operation and at high voltage. Temperature higher than 235 °C was achieved at 7 V without failure.

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The seed surface preparation for SiC sublimation growth has been investigated. Two methods have been developed to prepare and improve the seed surface contribution during the growth initiation:-An in-situ sublimation etching of the seed is performed.-The seed surface is prepared by ex-situ polishing and chemical and ozone cleaning.Both methods promote a better lateral growth mechanism, and then promote the prefered step flow growth mechanism. This results in a better crystalline quality of the crystals in terms of mosai:city, polytype stability and micropipe density.

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