Особенности влияния условий роста на структурные и оптические свойства пленок Zn0.9Cd0.1O

The influence of the magnetron power and the gas ratio Ar/O2 on the microstructure and the optical properties of Zn0.9Cd0.1O films is studied. The films were deposited with the use of the dc magnetron sputtering technique at a temperature of 250 ◦C. Atomic force microscopy (AFM) and X-ray diffraction (XRD) researches of a surface morphology demonstrated a strong influence of deposition procedure parameters on the film microstructure. The XRD analysis revealed that all grown films were polycrystalline and single-phase. The increase of the gas ratio Ar/O2 was found to be beneficial for the crystalline structure of Zn0.9Cd0.1O ternary alloys. Peculiarities of the control over the band gap and the surface morphology for Zn0.9Cd0.1O ternary alloys by varying the growth parameters are discussed.Дослiджено вплив потужностi магнетрона i спiввiдношення тискiв робочих газiв Ar/O2 на мiкроструктуру та оптичнi властивостi плiвок Zn0.9Cd0.1O. Плiвки осаджено методом магнетронного розпилювання на постiйному струмi при температурi пiдкладки 250 C. Дослiдження морфологiї поверхнi, здійснені за допомогою атомно-силової мiкроскопiї (АСМ), i рентгено-фазовий аналiз (РФА) виявили сильний вплив технологічних параметрiв осадження на мiкроструктуру плiвок. РФА аналiз показав, що всi вирощенi плiвки є полiкристалiчними i однофазними. Встановлено, що зростання парцiального тиску аргону в газовiй сумiшi Ar/O2 сприятливо впливає на кристалічну структуру твердих розчинiв Zn0.9Cd0.1O. Обговорено особливостi контролю ширини забороненої зони та морфологiї поверхнi твердих розчинiв Zn0.9Cd0.1O шляхом змiни параметрiв вирощування.В работе исследовано влияние мощности магнетрона и соотношения давлений рабочих газов Ar/O2 на микроструктуру и оптические свойства пленок Zn0.9Cd0.1O. Пленки осаждены методом магнетронного распыления на постоянном токе при температуре подложки 250 C. Исследования морфологии поверхности, проведенные с помощью атомно-силовой микроскопии (АСМ), и рентгенофазовый анализ (РФА) выявили сильное влияние технологических параметров роста на микроструктуру пленок. РФА анализ показал, что все выращенные пленки являются поликристаллическими и однофазными. Было установлено, что рост парциального давления аргона в газовой смеси Ar/O2 благоприятно влияет на кристаллическую структуру твердых растворов Zn0;9Cd0;1O. Обсуждены особенности контроля ширины запрещенной зоны и морфологи поверхности твердых растворов Zn0;9Cd0;1O путем изменения параметров осаждени

Calculation of the Unstable Mixing Region in Zn1−xCdxOZn_{1-x}Cd_xO Ternary Alloys

The $Zn_{1-x}Cd_xO$ ternary alloys with a narrow band gap, which are useful for light emitters in the visible wavelengths, are studied with respect to the unsteady region in mixing. This unstable region in mixing is calculated from the free energy of mixing using the strictly regular solution model. The interaction parameter used in this calculation is obtained by means of the valence-force-field model. An influence of the strain energy induced by substrate on the region of the spinodal decomposition for the $Zn_{1-x}Cd_xO$ system is studied and discussed

Free-standing and substrate-supported 2D noble metals

In this research, the primary hypothesis centers on investigating the potential of 2D noble metals (Ag, Au, Ir, Os, Pd, Pt, Rh, Ru) as efficient catalysts for the hydrogen evolution reaction (HER). This study encompasses four distinct scenarios:1.Free-Standing 2D Noble Metals: The intrinsic properties of standalone 2D noble metal layers are examined.2.2D Noble Metals on 4H-SiC: The influence of 4H-SiC as a substrate on the properties of these 2D noble metal layers is explored.3.2D Noble Metals on Buffer Layer/4H-SiC: A buffer layer is introduced between the 2D noble metals and 4H-SiC to investigate its impact on catalytic properties.4.2D Noble Metals on Epitaxial Graphene/4H-SiC: The use of epitaxial graphene as an additional layer between 2D noble metals and 4H-SiC is considered to study its effects.To gain insights into the structure, electronic properties, and catalytic capabilities of these configurations, extensive Density Functional Theory (DFT) calculations were conducted employing the SIESTA package. The calculations utilized the vdW-BH functional in conjunction with a double-ζ polarized (DZP) basis set, ensuring accuracy in the results.The research dataset presented encompasses a range of critical information:1.XSF Structure Files: These files provide the atomic coordinates and structural details of the optimized configurations of 2D noble metals both before and after hydrogen adsorption, facilitating a deep understanding of their geometric transformations during catalysis.2.Vesta-Generated TIFF Files (Side and Top Views): These images depict the optimized structures of 2D noble metals before and after hydrogen adsorption, offering visual insights into the morphological changes these materials undergo during the catalytic process.3.Txt and MATLAB-Generated TIFF Files: These files contain essential data, including the xy-plane-averaged 1D charge density difference (CDD) for all considered structures. This data is invaluable for understanding the interfacial charge transfer. Additionally, the results of charge population analyses using Hirshfeld and Voronoi schemes are included, aiding in the characterization of charge distribution.4.GaussView 6-Generated Cube and Vesta-Generated TIFF Files: These files contain the 3D charge density difference (CDD) information for all considered structures. This data enables researchers to delve into the spatial distribution of charge density changes.The research dataset serves as a comprehensive resource for those interested in exploring the electronic and catalytic properties of 2D noble metals in various configurations. It not only offers detailed structural and electronic information but also provides the foundation for further investigations and the development of efficient catalysts. Researchers can use this dataset to replicate the findings, build upon the work, and contribute to advancements in catalysis science.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Phase Field Modeling of the Zn1−xCdxOZn_{1-x}Cd_xO Solid Solutions

The analysis of spinodal decomposition in the $Zn_{1-x}Cd_xO$ ternary alloy was carried out by means of the nonlinear Cahn-Hilliard equation. Interaction parameter as a function of composition x was provided by valence force field simulations and was used in this analysis. The morphological patterns for the ternary alloys with different Cd content (x=5, 10, 50%) were experimentally obtained using the semi-implicit Fourier-spectral method. The simulated microstructure evolution $Zn_{0.95}Cd_{0.05}O$ demonstrates that the microstructure having a form of bicontinuous worm-like network is evolved with the progress of aging. An effect of the phase-field mobility and the gradient energy on the microstructure evolution of the $Zn_{1-x}Cd_xO$ alloys is discussed. It was found that the higher driving force for the decomposition in the higher Cd content film results in a higher decomposition rate revealed by the simulations. The temporal evolution of the simulated $Zn_{0.95}Cd_{0.05}O$ microstructure is in good agreement with experimental results, which have been obtained for this solid solution

Study of the Clusterization of CdO Phase in ZnCdO Alloys by Modeling Fullerene-Like Zn 44

The structural, cohesive and electronic properties of fullerene-like isolated Zn₄₄Cd₄O₄₈ cluster with consideration of CdO phase clusterization are studied in the frames of density functional theory B3LYP/3-21G(d). It is revealed that an enlargement of CdO phase content in Zn₄₄Cd₄O₄₈ cluster leads to nonlinear rapid increase in cohesive energy and cluster stability, as well as band-gap energy shrinkage

Study of the clusterization of CdO phase in ZnCdO alloys by modeling fullerene-like Zn₄₄Cd₄O₄₈ cluster

The structural, cohesive and electronic properties of fullerene-like isolated Zn₄₄Cd₄O₄₈ cluster with consideration of CdO phase clusterization are studied in the frames of density functional theory B3LYP/3-21G(d). It is revealed that an enlargement of CdO phase content in Zn₄₄Cd₄O₄₈ cluster leads to nonlinear rapid increase in cohesive energy and cluster stability, as well as band-gap energy shrinkage

Complementary study of the photoluminescence and electrical properties of ZnO films grown on 4H-SiC substrates

We have studied the photoluminescence and electrical properties of ZnO films grown epitaxially by atmospheric pressure MOCVD on 4H-SiC substrates. The dominating D°X line on the low temperature PL spectrum is attributed to the emission of an exciton bound to the neutral donor. The intensity of this line correlates with the electrical properties of the films: the decrease of D°X intensity occurs simultaneously with the increase of the carrier׳s mobility. This we explain as donor activation providing free electrons to the conduction band. Based on the comparison of the calculated value of donor binding energy, the literature data and complementary SIMS analysis a suggested donor impurity is aluminum (Al). The exciton localization energy is 16.3 meV, and agrees well with localization energy of 15.3 meV for Al impurity reported by other authors (e.g. Ref. [33]). The thermal activation energy ED=22 meV, determined from the Hall data and is in agreement with the optical activation energy ~20 meV, which is derived from the temperature-dependent PL study. The calculated value of the donor binding energy of 54.3 eV is in agreement with the ionization energy of 53 meV mentioned in earlier reports for Al in ZnO films. Our results prove that the commonly observed line at ~3.3599 eV on low temperature PL spectra of ZnO is a neutral donor bound exciton emission due to the Al impurity

Band-gap engineering of ZnO1-xSx films grown by rf magnetron sputtering of ZnS target

Structural and optical properties of ZnO1-xSx (0 less than= x less than= 1.0) thin films grown onto sapphire substrates (c-Al2O3) at 300 degrees C by radio frequency (rf) magnetron sputtering of ZnS ceramic target are studied. A possibility of purposeful controlling sulfur content and, as consequence, ZnO1-xSx band gap energy via changing the ratio of the partial pressures of argon and oxygen are revealed. Linear dependence of ZnO lattice parameter c on S content suggests that structural properties of single-phase ternary alloys in the composition range between ZnO and ZnS obey Vegards law. The mechanisms of influence of gas mixing ratio on film growth and band gap energy are discussed. Cu(In,Ga)Se-2 (CIGS)-based heterojunction solar cells with ZnO1-xSx buffer layers were fabricated by one-cycle magnetron sputtering procedure. Electrical characteristics of Cd-free devices are comparable to those of CdS-containing photovoltaic heterostructures, thereby indicating prospects of using ZnO1-xSx layers for fabrication of CIGS solar cells. (C) 2015 Elsevier Ltd. All rights reserved.Funding Agencies|Swedish Institute</p

Light emission enhancement from ZnO nanostructured films grown on Gr/SiC substrates

We report on the application of a single layer graphene substrates for the growth of polycrystalline ZnO films with advanced light emission properties. Unusually high ultraviolet (UV) and visible (VIS) photoluminesce was observed from the ZnO/Gr/SiC structures in comparison to identical samples without graphene. The photoluminescence intensity depends non-monotonically on the films thickness, reaching its maximum for 150 nm thick films. The phenomena observed is explained as due to the dual graphene role: i) the dangling bond free substrate, providing growth of relaxed thin ZnO layers ii) a back reflector active mirror of the Fabry-Perot cavity that is formed. The reported results demonstrate the potential of two-dimensional carbon materials integration with light emitting wide band gap semiconductors and can be of practical importance for the design of future optoelectronic devices.Funding agencies:  Linkoping Linnaeus Initiative for Novel Functional Materials (LiLi-NFM); Angpanneforeningens Forskningsstiftelse [14-517]; European Union [604391]</p