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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]

Although vanadium compounds are well recognized for their ability to change from insulator to metal, they may also be used therapeutically to address significant medical issues. In this study, we used vanadium oxide thin films synthesized by the pulsed laser deposition (PLD) technique to examine human stem cells generated from bone marrow. According to x-ray reflectivity (XRR) measurements, the films' thickness ranged from 6 to 26 nm. The water contact angle method has been employed to probe the surface energy and wettability of the films, which influence the cell behavior significantly. We also used a variety of techniques, such as differentiation staining, phase contrast microscopy, and real-time reverse transcription-polymerase chain reaction (RT-PCR), to examine the growth, adhesion, proliferation, and differentiation of human bone marrow mesenchymal stem cells (hBMMSCs) on these oxide films over time. Our results indicated that vanadium oxide films alter hBMMSCs adhesion and growth and affect their differentiation. The application of VOx films in biological and medical materials, as well as future research on cells, is all made possible by these findings, which also improve our understanding of the biological actions of vanadium compounds. [ABSTRACT FROM AUTHOR]

Since SrVO3 (SVO) can be used as a highly conductive material for perovskite heterostructures, the control of surface morphology and chemistry of such thin‐films are essential. Using pulsed laser deposition, two distinct topographies can be produced. Thus, by tuning oxygen pressure in the growth chamber during cooling, smooth or partially covered by self‐oriented Sr3V2O8 nanorods surfaces can be grown. This study manages to correlate the two typical topographies, revealed by atomic force microscopy (AFM), with their chemical compositions obtained by X‐ray photoelectron spectroscopy (XPS). At first, a model describes their initial surface chemistry through the Sr/V cationic ratio and the (Sr+V)/Oox ratio. Furthermore, using sputter‐depth profiling, post‐thermal treatments and wet chemical etching, SVO thin‐film chemical compositions are extensively studied. We demonstrate that they are composed of stoichiometric SVO phase covered by Sr‐rich layer on top. Finally, treatment in water for 180 seconds helps to remove Sr‐rich phases. Sr3V2O8 nanorods are found selectively dissolved leaving a surface nano‐imprint. Moreover, on smooth SVO surfaces, a balanced Sr/V cationic ratio of 1.0±0.1 is obtained. These results appear very promising for SVO thin‐films surface preparation and further development as electrodes for electronic devices. [ABSTRACT FROM AUTHOR]

Two-phase, vertical nanocomposite heteroepitaxial films hold great promise for (multi)functional device applications. In order to achieve practical devices, a number of hurdles need to be overcome, including the creation of ordered structures (and their formation on a large scale), achieving different combinations of materials and control of strain coupling between the phases. Here we demonstrate major advances on all these fronts: remarkable spontaneously ordered structures were produced in newly predicted compositions, vertical strain was proven to dominate the strain state in films above 20 nm thickness and strain manipulation was demonstrated by selection of phases with the appropriate elastic moduli. The work opens up a new avenue for strain control in relatively thick films and also promises new forms of ordered nanostructures for multifunctional applications. [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]

[Display omitted] • Amorphous and anatase TiO 2 thin films deposited by ALD. • Crystallization threshold temperature depending on the substrate (Si or glass). • Comparison of structural and optical properties of TiO 2 deposited on Si and glass. • Identification and confirmation of a growth model. • Wide evolution of polarizability vs material density, independent of the set-up. • High and frequency-independent dielectric constant with low losses. TiO 2 films were deposited by ALD on Si and glass substrates. FTIR analysis reveals an incomplete process for deposition temperatures below 160 °C. The transition from the amorphous to the crystallized anatase phase is observed during the variation of the deposition temperature. Films were uniform and homogeneous, with a crystallization threshold temperature depending on the substrate's nature. This delay in crystallization temperature was highlighted by many characterization techniques and found higher by about 50 °C on glass compared to Si substrate. We have also identified the determining role of the deposition temperature and the thickness in the crystallization process and we propose a growth model, independently of the substrate's nature, using different structural analyses. TiO 2 refractive index (n) and extinction coefficient (k) were studied at various deposition temperature. The evolution of the TiO 2 polarizability (α opt) with material density was determined from n values, showing a large variation of polarizability as a function of material density, in agreement and complementary with other studies. The investigation of the dielectric properties at low frequency shows that the losses and relaxation in TiO 2 decrease with deposition temperature, reaching at 300 °C a high and frequency-independent dielectric constant, close to the one reported for polycrystalline anatase. [ABSTRACT FROM AUTHOR]

Abstract: Pulsed Laser Deposition of magnetically ordered polycrystalline SmFeO3 films has been optimized onto SiO2 glass substrates as function of substrate temperature, oxygen pressure and pulsed laser fluency. Using a KrF excimer laser, crystallization temperature is found to be about 1048K for a weak fluency of only 1.7Jcm−2. We show that this growth temperature can be reduced using higher fluency and that it is possible to obtain a film texturation along the c axis by reducing the oxygen pressure at given temperature and fluency. In a second part, we focus on the SmFeO3 optical constants determined by in situ ellipsometry using a stacking model and the Cauchy dispersion relation for SmFeO3 layer. We show a good correlation between the transmission and reflection calculated from these data and measured by ex situ spectrophotometry in the visible range. [Copyright &y& Elsevier]

[Display omitted] • Sr-rich phases onto SrVO 3 thin films are studied using Angle Resolved XPS. • A treatment in water removes Sr excess by giving a V-OH terminated surface. • A study of air-ageing onto "as-grown" and "H 2 O-treated" SVO is finally pursued. In this work, 40 nm-thick films of SrVO 3 (SVO) grown by Pulsed Laser Deposition (PLD) on SrTiO 3 substrates are studied by X-Ray Photoelectron Spectroscopy (XPS). We develop here a systematic fitting procedure for both Sr3d, V2p 3/2 and O1s spectral regions of interest associated to the different chemical environments. Joint angle resolved XPS and Ar ion depth profiling reveal that as-grown SVO thin films exhibits Sr-rich phases at the extreme surface and a near-stoichiometric SVO in the bulk. The removal of segregated Sr is proposed by a treatment in deionized ultrapure water. This step will become an essential technological step in order to obtain reproducible surfaces achieving a stoichiometric SVO oxide phase. Besides, these hydrolyzed SVO surfaces appears VO 2 terminated and then more electrically active. Furthermore, an air-ageing comparative study between as-grown and H 2 O-treated samples reveals that hydrolyzed surfaces are more surface sensitive to air oxidation. Such observations will be crucial and must be carefully considered before performing any passivation process for the integration of SVO thin film into next generation electronics heterostructures. [ABSTRACT FROM AUTHOR]