CuInSe2 (CIS) layers were grown by co-evaporation in a molecular beam epitaxy system onto soda lime glass substrates by using both two-step and three step processes. The physical properties of the layers were investigated using X-ray diffraction (XRD) and optical spectroscopy. The sample atomic composition was assessed by energy dispersive analysis of X-rays. Cu-rich or In-rich CIS thin films were obtained exhibiting strong preferential (112) and (220)/(204) orientations in both cases. We performed thermal annealing at 450 °C under nitrogen, keeping Se overpressure to avoid Se desorption from the layer. The annealed layers all exhibit improved crystalline quality, with reduced stoichiometric discrepancy. The secondary phases like CuxSe1 − x or InxSe1 − x are no more observable by XRD measurements. Regarding the preferential orientation, thermal annealing of Cu-rich CIS layers favours the (112) orientation leading to a more (112) textured layer after annealing, whatever the initial preferential growth orientation was. In opposite, thermal annealing of In-rich samples increases the (220)/(204) texture of the sample.

We present a study of non-intentionally doped InN epilayers directly grown on sapphire substrate by metal organic chemical vapour deposition (MOCVD) technique. Structural and optical characterisations of this sample have been conducted by SEM, temperature-dependent photoluminescence and time resolved pump-probe techniques. Triangular-shaped structures of InN are observed to grow above hexagonal-shaped columnar structures as seen from the SEM image. Photoluminescence spectra reveal a peak energy of 0.75 eV, supporting the existence of the narrow bandgap of InN. So far, various papers in the literature quote the carrier lifetime in InN epilayers grown on sapphire substrate in the presence of a buffer layer such as GaN. Herein, we report carrier lifetime measurements conducted on InN epilayer deposited directly on sapphire substrate, in the absence of GaN as a buffer layer.

In this work, we present a comprehensive study on the hydrogen impurity depth profiles in InN films with polar c-plane and nonpolar a-plane surface orientations in relation to their structural and free-electron properties. We find that the as-grown nonpolar films exhibit generally higher bulk and near-surface H concentrations compared to the polar InN counter-parts. The latter may be partly associated with a change in the growth mode from 2D to 3D and a decrease in the grain size. Thermal annealing leads to a reduction of H concentrations and the intrinsic H levels are influenced by the structural characteristics of the films. The factors allowing reduction of bulk H and free electron concentrations in a-plane films are discussed. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

L’électronique envahit de plus en plus notre quotidien, elle est omniprésente. Les matériaux semi-conducteurs sont à la base de cette industrie – mais qu’est-ce qu’un semiconducteur ? Tout le monde a entendu parler du silicium, qui règne en maître dans ce domaine, mais de nombreux autres matériaux sont utilisés, d’autant plus que leur champ d’application s’étend maintenant à de nombreuses autres disciplines, comme les sciences du vivant par exemple. Grâce à la physique quantique, nous savons même aujourd’hui dépasser les possibilités des matériaux naturels, en les structurant à une échelle micro ou nanométrique, de manière à ajuster à la demande leurs propriétés aux applications envisagées. Dans cet exposé, je ferais un panorama de cette évolution et je présenterai les directions de recherche poursuivie dans le département « semiconducteurs, matériaux et capteurs » du laboratoire Charles Coulomb, afin d’illustrer les perspectives immenses offertes par cette classe de matériaux.

Considerable advances in materials science are expected via the use of selected or designed peptides to recognize material, control their growth, or to assemble them into elaborate novel devices. Identifying specific peptides for a number of technologically useful materials has been the challenge of many research groups in recent years. This can be accomplished by using affinity-based bio-panning methods such as phage display technologies. In this work, a combinatorial library including billions of clones of genetically engineered M13 bacteriophage was used to select peptides that could recognize improved indium nitride (InN) semiconductor (SC) material. Several rounds of biopanning were necessary to select the phage with the higher affinity from the low variant library. The DNA of this specific phage was extracted and sequenced to set up the related specific adherent peptide. Atomic force microscopy (AFM) is used to demonstrate the real affinity of a selected phage for the InN surface. Due to the possibility of its functionalization with biomolecules and its important physical properties, InN is a promising candidate for developing affinity-based optical and electrical biosensors and/or for biomimetic applications. Copyright (C) 2010 European Peptide Society and John Wiley & Sons, Ltd.