Narrow Results

(La_2/3-xY_x) (Ca_1/3-ySr_y) MnO₃ (LYCSMO) thin films with x = 0.08 and y = 0.0868 deposited on SrTiO₃ (STO), Yttrium-stabilized ZrO₂ (YSZ), LaAlO₃ (LAO), and MgO substrates are fabricated. Atomic force microscopy measurements reveal that the morphology is quite different for all films. A two-dimensional growth mode is suitable for LYCSMO film on STO, while on LAO, YSZ, and MgO, an island growth mode may be a good description for the growth of LYCSMO films. X-ray diffraction studies show that the films epitaxially grow along c axis on STO, LAO, and MgO substrates, while grows along a axis on YSZ substrate. The in-plane and out-of-plane lattice parameters are also obtained for films grown on all substrates.

Molybdenum thin films were sputter deposited under different conditions of DC power and chamber pressure. The structure and topography of the films were investigated using AFM, SEM and XRD techniques. Van der Pauw method and tape test were employed to determine electrical resistivity and interfacial strength to the substrate, respectively. All the films are of sub-micron thickness with maximum growth rate of 78 nm/min and crystallite size in the range of 4 to 21 nm. The films produced at high power and low pressure exhibit compressive residual strains, low electrical resistivity and poor adhesion to the glass substrate, whereas the converse is true for films produced at high pressure.

In this work, we prepared LaNiO₃ (LNO) and Au-LaNiO₃ (Au-LNO) films using sol–gel multilayer coating method. The effects of lattice mismatch on the microstructure and electrical properties of the films were investigated by choosing different single-crystal substrate. XRD, SEM, and AFM results showed the high quality of LNO and Au-LNO films, indicating the successful epitaxial growth of the films on the single-crystal substrates. The room temperature resistivity of LNO films increased with the increase of lattice mismatch while different tendency was observed in Au-LNO films, suggesting that different mechanisms prevailed in the LNO and Au-LNO films. Both the transport behavior and the residual resistivity ratio were checked to explore the relationship between the lattice mismatch and the electrical properties of the films. Strain and defect concentration were proposed as the predominating factors for the changes in the resistivity of LNO and Au-LNO films under the influence of lattice mismatch.

A comprehensive theoretical study has been carried out to examine the electronic and thermoelectric properties of As$XY$ (where $X=\mathrm{\text{S}}$, Se; $Y=\mathrm{\text{Cl}}$, Br, and I) monolayers. The lattice constants of these monolayers are optimized to determine their most stable configurations. The electronic and thermoelectric characteristics of these monolayers are calculated using state-of-the-art computational methods. Specifically, the first-principles calculations in combination with semiclassical Boltzmann transport theory were employed to gain insights into their behavior. One of the crucial findings of the study is the observation of an indirect band nature in all the studied monolayers. This characteristic provides valuable information about the materials’ electronic behavior and potential applications. Furthermore, the impacts of tensile and compressive strains on these monolayers are investigated. Interestingly, we observed changes in the band value when strain is applied, which opens up exciting possibilities for engineering their electronic properties. Importantly, despite these changes, the band nature of the monolayers remains consistent. In particular, it is found that the AsSI monolayer exhibits a remarkable enhancement in the Seebeck coefficient, both in the unstrained state and under a compressive strain of 4% in the p-type region. This enhancement leads to a higher power factor (PF), suggesting that AsSI monolayers could be promising candidates for efficient thermoelectric devices. Overall, these findings highlight the potential of strain engineering to tailor the electronic properties of As$XY$ monolayers, offering exciting opportunities for their application in thermoelectric devices. This research contributes valuable insights into the design and optimization of novel materials for future energy conversion and electronic applications.

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