Abstract In a 2D electron system (2DES) the breaking of the inversion, time‐reversal and bulk crystal‐field symmetries is interlaced with the effects of spin‐orbit coupling (SOC) triggering exotic quantum phenomena. Here, epitaxial engineering is used to design and realize a 2DES characterized simultaneously by ferromagnetic order, large Rashba SOC and hexagonal band warping at the (111) interfaces between LaAlO 3 , EuTiO 3 , and SrTiO 3 insulators. The 2DES displays anomalous quantum corrections to the magneto‐conductance driven by the time‐reversal‐symmetry breaking occurring below the magnetic transition temperature. The results are explained by the emergence of a non‐trivial Berry phase and competing weak anti‐localization/weak localization back‐scattering of Dirac‐like fermions, mimicking the phenomenology of gapped topological insulators. These findings open perspectives for the engineering of novel spin‐polarized functional 2DES holding promises in spin‐orbitronics and topological electronics.

Raman spectroscopy is a widely used technique to characterize nanomaterials because of its convenience, non-destructiveness, and sensitivity to materials change. The primary purpose of this work is to determine via Raman spectroscopy the average thickness of MoS 2 thin films synthesized by direct liquid injection pulsed-pressure chemical vapor deposition (DLI-PP-CVD). Such samples are constituted of nanoflakes (with a lateral size of typically 50 nm, i.e., well below the laser spot size), with possibly a distribution of thicknesses and twist angles between stacked layers. As an essential preliminary, we first reassess the applicability of different Raman criteria to determine the thicknesses (or layer number, N ) of MoS 2 flakes from measurements performed on reference samples, namely well-characterized mechanically exfoliated or standard chemical vapor deposition MoS 2 large flakes deposited on 90 ± 6 nm SiO 2 on Si substrates. Then, we discuss the applicability of the same criteria for significantly different DLI-PP-CVD MoS 2 samples with average thicknesses ranging from sub-monolayer up to three layers. Finally, an original procedure based on the measurement of the intensity of the layer breathing modes is proposed to evaluate the surface coverage for each N (i.e., the ratio between the surface covered by exactly N layers and the total surface) in DLI-PP-CVD MoS 2 samples.

La détection des micropolluants dans les milieux aqueux représente un enjeu crucial pour la protection de l'environnement. Cette étude présente le développement de micro-capteurs électrochimiques à base de graphène pour détecter l'isoproturon : un herbicide classé comme micropolluant prioritaire nécessitant un suivi dans les masses d’eau de la communauté européenne. Le graphène employé pour cette étude est synthétisé par dépôt chimique en phase vapeur (CVD) sur cuivre. La fabrication de l’électrode est décrite et étayée par des caractérisations physiques (optique, électronique) et électrochimiques. Les résultats obtenus sur le graphène fonctionnalisé par un polymère à empreintes moléculaires (MIP) ont conduit à une sensibilité et une sélectivité qui démontrent le potentiel des capteurs à base de graphène pour la surveillance environnementale.

This paper presents the reproducible DLI-MOCVD of MoS 2 on Si/SiO 2 from benign precursors, with very high photoluminescence on a cm-scale area.

Shunt resistance Rsh is a critical parameter for photovoltaic cells designed for low light indoor applications because it negatively affects the open circuit voltage, fill factor, and conversion efficiency. Standard CIGS cells are known to have low Rsh and are, therefore, unpromising candidates for indoor energy sources. In this paper, we extend the original work of Virtuani et al. by determining the electrical specifications of many CIGS cells with copper contents [Cu]/([Ga]+[In]) as low as 0.33 and gallium contents between 0.28 and 0.81. First, IV data are fitted by a standard single-diode electrical circuit model for each illumination, resulting in light-dependent parameters. Then, we use a procedure based on a single dataset of electrical variables, i.e., independent of light, corrected by the experimental collection function, which captures light-dependent physical mechanisms. In this way, we are able to correctly reproduce the illuminance dependence of the electrical response of the PV cell over three orders of magnitude, in particular with a fixed value of the shunt resistance. The highest Rsh is obtained with a low copper composition of 0.5, regardless of the gallium composition.

We report on the coexistence of both normal and topological insulating phases in InAs/GaSb bilayer quantum well induced by the built-in electric field tuned optically and electrically. The emergence of topological and normal insulating phases is assessed based on the evolution of the charge carrier densities, the resistivity dependence of the gap via in-plane magnetic fields and the thermal activation of carriers. For the Hall bar device tuned optically, we observe the fingerprints associated with the presence of only the topological insulating phase. For another Hall bar processed identically but with an additional top gate, the coexistence of normal and topological insulating phases is found by electrical tuning. Our finding paves the way for utilizing a new electro-optical tuning scheme to manipulate InAs/GaSb bilayer quantum wells to obtain trivial-topological insulating interfaces in the bulk rather than at the physical edge of the device.