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In the search of low cost and more efficient electronic devices, here the properties of SrVO3 transparent conductor oxide (TCO) thin film are investigated, both visible‐range optically transparent and highly conductive, it stands as a promising candidate to substitute the standard indium‐tin‐oxide (ITO) in applications. Its surface stability under water (both liquid and vapor) and other gaseous atmospheres is especially addressed. Through the use of spectroscopy characterizations, X‐ray photoemission and operando X‐ray absorption measurements, the formation of a thin Sr‐rich V5+ layer located at the surface of the polycrystalline SrVO3 film with aging is observed, and for the first time how it can be removed from the surface by solvating in water atmosphere. The surface recovery is associated to an etching process, here spectroscopically characterized in operando conditions, allowing to follow the stoichiometric modification under reaction. Once exposed in oxygen atmosphere, the Sr‐rich V5+ layer forms again. The findings improve the understanding of aging effects in perovskite oxides, allowing for the development of functionalized films in which it is possible to control or to avoid an insulating surface layer. This constitutes an important step towards the large‐scale use of V‐based TCOs, with possible implementations in oxide‐based electronics. [ABSTRACT FROM AUTHOR]

The characterization of silicon carbide (SiC) by specific electrical atomic force microscopy (AFM) modes is highly appreciated for revealing its structure and properties at a nanoscale. However, during the conductive AFM (C-AFM) measurements, the strong electric field that builds up around and below the AFM conductive tip in ambient atmosphere may lead to a direct anodic oxidation of the SiC surface due to the formation of a water nanomeniscus. In this paper, the underlying effects of the anodization are experimentally investigated for SiC multilayers with different doping levels by studying gradual SiC epitaxial-doped layers with nitrogen (N) from 5 × 1017 to 1019 at/cm3. The presence of the water nanomeniscus is probed by the AFM and analyzed with the force–distance curve when a negative bias is applied to the AFM tip. From the water meniscus breakup distance measured without and with polarization, the water meniscus volume is increased by a factor of three under polarization. AFM experimental results are supported by electrostatic modeling to study oxide growth. By taking into account the presence of the water nanomeniscus, the surface oxide layer and the SiC doping level, a 2D-axisymmetric finite element model is developed to calculate the electric field distribution nearby the tip contact and the current distributions at the nanocontact. The results demonstrate that the anodization occurred for the conductive regime in which the current depends strongly to the doping; its threshold value is 7 × 1018 at/cm3 for anodization. Finally, the characterization of a classical planar SiC-MOSFET by C-AFM is examined. Results reveal the local oxidation mechanism of the SiC material at the surface of the MOSFET structure. AFM topographies after successive C-AFM measurements show that the local oxide created by anodization is located on both sides of the MOS channel; these areas are the locations of the highly n-type-doped zones. A selective wet chemical etching confirms that the oxide induced by local anodic oxidation is a SiOCH layer. [ABSTRACT FROM AUTHOR]

Memristors are expected to be one of the key building blocks for the development of new bio-inspired nanoelectronics. Memristive effects in transition metal oxides are usually linked to the electromigration at the nanoscale of charged oxygen vacancies (OV). In this paper we address, for Pt/TiO x /TaO y /Pt devices, the exchange of OV between the device and the environment upon the application of electrical stress. From a combination of experiments and theoretical simulations we determine that both TiO x and TaO y layers oxidize, via environmental oxygen uptake, during the electroforming process. Once the memristive effect is stabilized (post-forming behavior) our results suggest that oxygen exchange with the environment is suppressed and the OV dynamics that drives the memristive behavior is restricted to an internal electromigration between TiO x and TaO y layers. Our work provides relevant information for the design of reliable binary oxide memristive devices. [ABSTRACT FROM AUTHOR]

Indium‐tin‐oxide (ITO) is a widely employed transparent conducting oxide (TCO), but the indium scarcity and price encourage developing some alternatives. The correlated metals CaVO3 and SrVO3 have been recently identified as new TCOs with functional properties being comparable to ITO. However, their technological potential is limited by the critical requirement of a perovskite structure of the film, impossible to achieve via direct growth on substrates commonly used for applications. In this article, the authors tackle this limitation by demonstrating the crystalline growth of vanadate TCOs on glass at temperatures below 600 °C, with the help of 2D nanosheets as transparent seed layers. The functional properties do not suffer from the textured structure of the films, as confirmed by an in‐depth spectroscopic ellipsometry study, allowing for an industrially viable approach to integrate vanadate TCOs on virtually any surface and to exploit their promising performances as a new generation TCO. [ABSTRACT FROM AUTHOR]

Abstract: The (LaV3+O3)m/SrV4+O3 (m = 5, 6) superlattices are investigated by first principles calculations. While bulk LaVO3 is a C‐type antiferromagnetic semiconductor and bulk SrVO3 is a paramagnetic metal, semiconducting A‐type antiferromagnetic states for both superlattices are found due to epitaxial strain. At the interfaces, however, the V spins couple antiferromagnetically for m = 5 and ferromagnetically for m = 6 (m‐dependence of the magnetization). Electronic reconstruction in form of charge ordering is predicted to occur with V3+ and V4+ states arranged in a checkerboard pattern on both sides of the SrO layer. As compared to bulk LaVO3, the presence of V4+ ions introduces in‐gap states that strongly reduce the bandgap and influence the orbital occupation and ordering. [ABSTRACT FROM AUTHOR]

The experimental observation that vanadate superlattices (LaVO3)m/SrVO3 show ferromagnetism up to room temperature (LÜDERS U. et al., Phys. Rev. B, 80 (2009) 241102(R)) is investigated by means of density functional theory, and the band structure for m = 5 and 6 is calculated. A buckling of the interface VO2 layers is found in both cases, but subtle differences in bond length lead to very different properties for even and odd values of m: in the even case, the two interface VO2 layers effectively decouple from the adjacent LaO layers due to a strong bond length enhancement. This results into a local inversion of the orbital occupancy and to the confinement of the charge carriers. In the odd case, the amplitude of the bond length variation is smaller, so that the charge carriers spill into the deeper-lying VO2 layers, and spin-polarised interfaces are obtained. [ABSTRACT FROM AUTHOR]

The vanadate SrVO3 is a transparent conductor perovskite with optical and electrical properties competing with those of the most‐used indium tin oxide material. Although its charge density is comparable to that of metals, SrVO3 shows a plasma frequency below the visible range due to strong electronic correlations characterizing the electronic transport in this material and enhancing the effective mass. Therefore, the well‐known interplay between the structure and the electronic properties of strongly correlated systems can be used in such transparent conductor to tune the optical properties, as the plasma frequency also depends on the effective mass. In this study, SrVO3 films are grown by pulsed laser deposition onto different lattice mismatched perovskite substrates such as SrTiO3, LaAlO3, and (LaAlO3)0.3(Sr2TaAlO6)0.7 at different growth temperatures. The structural, electronic, and optical properties are analyzed, illustrating the influence of the strain on the structure of the films and on a shift of the plasma frequency. The electronic correlations in this new group of transparent conducting oxides can be therefore used as a supplementary lever for the tuning of the functional properties. SrVO3 thins films are grown by pulsed laser deposition onto SrTiO3, LaAlO3, and (LaAlO3)0.3(Sr2TaAlO6)0.7. Both optical and electrical properties of the films are investigated and demonstrate that such strongly correlated system is competing with the indium tin oxide as new transparent conducting oxide. The plasma frequency of the films depends on the substrate and can be easily tuned toward the infrared region. [ABSTRACT FROM AUTHOR]

Abstract: This article presents a review of the state of the art of materials used in spintronics. It is devoted to materials exhibiting novel and exciting electronic properties: manganites, double perovskites, spinel ferrites and diluted magnetic semiconductors. We present the main features of these classes of materials as well as the most important solid state physics results obtained from them in the field of spintronics. To cite this article: J. Cibert et al., C. R. Physique 6 (2005). [Copyright &y& Elsevier]

• Self organized epitaxial Sr 3 V 2 O 8 nanorods on SrVO 3 metallic matrix. • Specific local electric properties by conductive Atomic Force Microscopy and scanning tunneling microscopy. • Three dimensional resistance mapping of the nanorods by 3D-Spreading Resistance Microscopy mode. Self-organized epitaxial nanorods, obtained by an adapted annealing process after deposition of metallic strontium vanadate perovskite (SrVO 3) thin films, are analyzed to determine their structural, chemical and electrical properties. After the identification of the Sr 3 V 2 O 8 phase of the nanorods by electron diffraction; Electron Energy Loss Spectroscopy investigations show the vanadium oxidation state (V5+) for the nanorods. Two scanning probe techniques are deployed to determine the specific local electrical properties of these Sr 3 V 2 O 8 nanorods. In ambient conditions, local electrical properties are studied by Scanning Spreading Resistance Microscopy based on an Atomic Force Microscope and multiple probe scanning tunneling microscopy is used for the study in ultrahigh vacuum. Both techniques reveal that local electrical resistances of the nanorods are five order of magnitude higher than the resistance of the perovskite SrVO 3 matrix. Futhermore, the nanorods are found to be etched by repeating scanning of the conductive Atomic Force Microcopy probe, enabling a three-dimensional depth profile of the nanorods resistance with 3D-Spreading Resistance Microscopy mode. A partial embedding of the nanorods in the underlying SrVO 3 film is proved and the impact of the water meniscus at the origin of the selective etching observed during Scanning Spreading Resistance Microscopy, in ambient conditions, is discussed. [ABSTRACT FROM AUTHOR]

Correlated transparent conducting oxides (TCOs) have gained great attention, because of their unique combination of transparency and metallic character. SrVO 3 (SVO) was identified as a high-performance TCO in the visible range. Few studies have investigated band structure engineering through chemical doping to enhance the optical properties of SVO. Here, we use two different strategies by exploiting the band-filling and width of the bands derived from Vanadium to tune the screened plasma frequency ω p * and the interband transition E p - d energy, corresponding to the optical transparency window edges. For control of the band-filling strategy, it is found that Titanium doped SVO has a wide transparency window, but such a composition does not maintain the high electrical conductivity required for TCO applications. Concerning the bandwidth strategy, the doping of SrVO 3 by Calcium shows that ω p * remains located in the IR range (1.12 eV), while E p - d is blue-shifted into the UV region (3.43 eV) due to reinforced electronic correlations. By an appropriate choice of dopant, we successfully increased the size of the transparency window by around 11% from 1.94 eV (SVO) to 2.30 eV (Calcium-doped SVO), while retaining high conductivity of around 2.30 × 10 4 (S·cm -1 ) and high charge carrier density of 2.93 × 10 22 cm -3 .

Metallic ferromagnetic transition metal dichalcogenides have emerged as important building blocks for scalable magnetic and memory applications. Downscaling such systems to the ultrathin limit is critical to integrate them into technology. Here, we achieved layer-by-layer control over the transition metal dichalcogenide Cr 1.6 Te 2 by using pulsed laser deposition, and we uncovered the minimum critical thickness above which room-temperature magnetic order is maintained. The electronic and magnetic structures are explored experimentally and theoretically, and it is shown that the films exhibit strong in-plane magnetic anisotropy as a consequence of large spin-orbit effects. Our study elucidates both magnetic and electronic properties of Cr 1.6 Te 2 and corroborates the importance of intercalation to tune the magnetic properties of nanoscale materials' architectures.

SrVO 3 (SVO) is a prospective candidate to replace the conventional indium tin oxide (ITO) among the new generation of transparent conducting oxide (TCO) materials. In this study, the structural, electrical, and optical properties of SVO thin films, both epitaxial and polycrystalline, are determined during and after heat treatments in the 150-250 °C range and under ambient environment in order to explore the chemical stability of this material. The use of these relatively low temperatures speeds up the natural aging of the films and allows following the evolution of their related properties. The combination of techniques rather sensitive to the film surface and of techniques sampling the film volume will emphasize the presence of a surface oxidation evolving in time at low annealing temperatures, whereas the perovskite phase is destroyed throughout the film for treatments above 200 °C. The present study is designed to understand the thermal degradation and long-term stability issues of vanadate-based TCOs and to identify technologically viable solutions for the application of this group as new TCOs.

The electronic and magnetic properties of (LaCrO 3 ) m /SrCrO 3 superlattices are investigated using first principles calculations. We show that the magnetic moments in the two CrO 2 layers sandwiching the SrO layer compensate each other for even m but give rise to a finite magnetization for odd m , which is explained by charge ordering with Cr 3+ and Cr 4+ ions arranged in a checkerboard pattern. The Cr 4+ ions induce in-gap hole states at the interface, implying that the transparent superlattices are p-type semiconductors. The availability of transparent p-type semiconductors with finite magnetization enables the fabrication of transparent magnetic diodes and transistors, for example, with a multitude of potential technological applications., Competing Interests: The authors declare that there are no conflicts of interest., (This journal is © The Royal Society of Chemistry.)

Memristors are expected to be one of the key building blocks for the development of new bio-inspired nanoelectronics. Memristive effects in transition metal oxides are usually linked to the electromigration at the nanoscale of charged oxygen vacancies (OV). In this paper we address, for Pt/TiO x /TaO y /Pt devices, the exchange of OV between the device and the environment upon the application of electrical stress. From a combination of experiments and theoretical simulations we determine that both TiO x and TaO y layers oxidize, via environmental oxygen uptake, during the electroforming process. Once the memristive effect is stabilized (post-forming behavior) our results suggest that oxygen exchange with the environment is suppressed and the OV dynamics that drives the memristive behavior is restricted to an internal electromigration between TiO x and TaO y layers. Our work provides relevant information for the design of reliable binary oxide memristive devices., (© 2022 IOP Publishing Ltd.)

This work addresses the need for a comprehensive methodology for nanoscale electrical testing dedicated to the analysis of both "front end of line" (FEOL) (doped semiconducting layers) and "back end of line" (BEOL) layers (metallization, trench dielectric, and isolation) of highly integrated microelectronic devices. Based on atomic force microscopy, an electromagnetically shielded and electrically conductive tip is used in scanning microwave impedance microscopy (sMIM). sMIM allows for the characterization of the local electrical properties through the analysis of the microwave impedance of the metal-insulator-semiconductor nanocapacitor (nano-MIS capacitor) that is formed by tip and sample. A highly integrated monolithic silicon PIN diode with a 3D architecture is analysed. sMIM measurements of the different layers of the PIN diode are presented and discussed in terms of detection mechanism, sensitivity, and precision. In the second part, supported by analytic calculations of the equivalent nano-MIS capacitor, a new multidimensional approach, including a complete parametric investigation, is performed with a dynamic spectroscopy method. The results emphasize the strong impact, in terms of distinction and location, of the applied bias on the local sMIM measurements for both FEOL and BEOL layers., (Copyright © 2020, Coq Germanicus et al.; licensee Beilstein-Institut.)

Advanced amorphous sub-nanometric laminates based on TiO 2 and Al 2 O 3 were deposited by atomic layer deposition at low temperature. Low densities of 'slow' and 'fast' interface states are achieved with values of 3.96 · 10 10 cm -2 and 4.85 · 10 -9 eV -1 cm -2 , respectively, by using a 40 nm laminate constituted of 0.7 nm TiO 2 and 0.8 nm Al 2 O 3 . The sub-nanometric laminate shows a low hysteresis width of 20 mV due to the low oxide charge density of about 3.72 · 10 11 cm -2 . Interestingly, such properties are required for stable and reliable performance of MOS capacitors and transistor operation. Thus, decreasing the individual layer thickness to the sub-nanometric range and combining two dielectric materials with oppositely charged defects may play a major role in the electrical response, highly promising for the application in future micro and nano-electronics applications.

Capacitors with a dielectric material consisting of amorphous laminates of Al2O3 and TiO2 with subnanometer individual layer thicknesses can show strongly enhanced capacitance densities compared to the bulk or laminates with nanometer layer thickness. In this study, the structural and dielectric properties of such subnanometer laminates grown on silicon by state-of-the-art atomic layer deposition are investigated with varying electrode materials. The laminates show a dielectric constant reaching 95 combined with a dielectric loss (tan δ) of about 0.2. The differences of the observed dielectric properties in capacitors with varying electrodes indicate that chemical effects at the interface with the TiN electrode play a major role, while the influence of the local roughness of the individual layers is rather limited.