Arnaud Mantoux

Organic light-emitting transistors using concentric source/drain electrodes on a molecular adhesion layer

Bottom-contact tetracene light-emitting transistors employing a mercaptosilane derivative self-assembled monolayer as adhesive between gold concentric interdigitated source/drain electrodes and SiO2 gate dielectric are described. Devices that employ the mercaptosilane adhesive have a higher mobility and electroluminescence compared to those employing a standard metallic adhesive. This is rationalized in terms of the large, well interconnected grains found in tetracene films deposited on substrates using the mercaptosilane adhesive. Our work represents a step forward in the understanding of physical processes at semiconductor/metal and semiconductor/dielectric interfaces in organic devices.

Undoped TiO2 and nitrogen-doped TiO2 thin films deposited by atomic layer deposition on planar and architectured surfaces for photovoltaic applications

Undoped and nitrogen doped TiO2 thin films were deposited by atomic layer deposition on planar substrates. Deposition on 3D-architecture substrates made of metallic foams was also investigated to propose architectured photovoltaic stack fabrication. All the films were deposited at 265 degrees C and nitrogen incorporation was achieved by using titanium isopropoxide, NH3 and/or N2O as precursors. The maximum nitrogen incorporation level obtained in this study was 2.9 at. %, resulting in films exhibiting a resistivity of 115 Omega cm (+/-10 Omega cm) combined with an average total transmittance of 60% in the 400-1000 nm wavelength range. Eventually, TiO2 thin films were deposited on the 3D metallic foam template.