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Self-aligned ZnO nanorods (NRs) were grown on n-Si(100) substrate by RF sputtering techniques. The NRs are uniformly grown on 2-inch wafer along [0001] direction. Single-crystalline wurtzite structure of ZnO NRs was confirmed by X-ray diffraction. The average diameter, height, and density of NRs are found 48 nm, 750 nm, and 1.26×1010 cm–2, respectively. The current-voltages (I-V) characteristics of ZnO NRs/Si heterojunction (HJ) were studied in the temperature range of 120–300K and it shows a rectifying behavior. Barrier height (ϕB) and ideality factor (η) were estimated from thermionic emission model and found to be highly temperature dependent in nature. Richardson constant (A*) was evaluated using Richardson plot of ln(Io/T2) versus q/kT plot by linear fitting in two temperature range 120–180K and 210–300 K. Large deviation in Richardson constant from its theoretical value of n-Si indicates the presence of barrier inhomogeneities at HJ. Double Gaussian distribution of barrier height with thermionic equation gives mean barrier heights of 0.55±0.01 eV and 0.86±0.02 eV for two different temperature regions 120–180K and 210–300 K, respectively. Modified Richardson plot provided two values of Richardson constant for two temperature regions. However, for higher temperature range (210–300 K), the calculated value of Richardson constant ~123 A cm–2 K–2 was close to the ideal Richardson constant for n-Si. [ABSTRACT FROM AUTHOR]

Herein, the hydrothermally derived, multilayered nanoscale WS2 subjected to 80 keV Xe+ ion irradiation with ion fluence varying in the range 1 × 1015–5 × 1016 ions cm−2 is reported. Transmission electron microscopy (TEM) imaging analysis reveals adequate splitting of stacks and consequent development of several layer sheets. Interestingly, the atomic force microscopy (AFM) studies exhibit several hillocks and craters in the postirradiated WS2, thereby enhancing the overall surface roughness (Rq) of specimens. Typically, Rq varies in the range 101–211 nm due to ion impact. This does not only influence the nature of visible emission features in the photoluminescence (PL) spectra but also Stoke's shift, suggesting strong electron–phonon coupling after radiation exposure. Moreover, Raman spectra of the studied systems reveal noticeable blue‐shifting of the Raman‐active E12g and A1g modes and also remarkable improvement in the E12g‐to‐A1g intensity ratio, ranging from 0.72 to 0.87. Finally, contact angle measurements carried out on specimen surfaces show a clear transition from the hydrophilic to hydrophobic behavior due to the irradiation‐induced increased surface roughness feature. The study can offer immense scope in components relevant to nano‐electromechanics, self‐cleaning, and nanocoatings and also where the switchable bifunctional property is invariably desired. [ABSTRACT FROM AUTHOR]

Metal oxide transistors have garnered substantial attention for their potential in low-power electronics, yet challenges remain in achieving both high performance and low operating voltages through solution-based fabrication methods. Optimizing interfacial engineering at the dielectric/semiconductor interface is of utmost importance in the fabrication of high-performance thin film transistors (TFTs). In the present article, a bilayer Ti3C2Tx-MXene/SnO2–semiconductor (Tx stands for surface termination) configuration is used to fabricate a high-performance n-type thin film transistor by using an ion-conducting Li-Al2O3 gate dielectric on a p+-Si substrate, where electrical charges are formed and modulated at the Li-Al2O3/SnO2 interface, and Ti3C2Tx-MXene nanosheets serve as the primary electrical charge channel due to their long lateral size and high mobility. A comparative characterization of two distinct TFTs is conducted, one featuring Ti3C2Tx MXene and SnO2 semiconductor layer and the other with SnO2 only. Notably, the TFT with the Ti3C2Tx MXene layer has shown a significant boost in the carrier mobility (10.6 cm2/V s), leading to remarkable improvements in the on/off ratio (1.3 × 105) and subthreshold swing (194 mV/decade), whereas the SnO2 TFT without the Ti3C2Tx MXene layer shows a mobility of 1.17 cm2/V s with 8.1 × 102 on/off ratio and 387 mV/decade subthreshold swing. This investigation provides a possible way toward the development of high-performance, low-voltage TFT fabrication with the MXene/semiconductor combination. [ABSTRACT FROM AUTHOR]

The radiation-resistant response of BaTiO3 in the tetragonal and rhombohedral phases on exposure to 100 MeV Ag7+ ion irradiation was investigated by in situ X-ray diffraction (XRD) at room temperature (300 K) and low temperature (25 K), respectively. This study revealed that the BaTiO3 in rhombohedral phase retained crystallinity up to an ion fluence of 1×1014 ions/cm2, whereas tetragonal phase amorphized at much lower fluence viz. 1×1013 ions/cm2. The in situ XRD along with Raman spectroscopy studies revealed that BaTiO3 in rhombohedral phase is more radiation resistant than that of tetragonal phase. The density functional theory ( DFT) calculations confirmed higher bond strength of rhombohedral phase as compared to tetragonal phase, which supported the experimental result of higher radiation stability of rhombohedral phase. The theoretical predictions on high-temperature phase will be of relevance to the nuclear waste applications. [ABSTRACT FROM AUTHOR]

In order to simulate radiation damages in tungsten, potential plasma facing materials in future fusion reactors, surrogate approach of heavy ion irradiation on polycrystalline tungsten is employed. Tungsten specimen is irradiated with gold heavy ions of energy 120 MeV at different fluences. Positron annihilation lifetime measurements are carried out on pristine and ion beam irradiated tungsten specimens. The variation in positron annihilation lifetime in ion irradiated specimens confirms evolution of vacancy clusters under heavy ion irradiation. The pristine and irradiated tungsten specimens have also been characterized for their microstructural, structural, electrical, thermal, and mechanical properties. X-ray diffractograms of irradiated tungsten specimens show structural integrity of polycrystalline tungsten even after irradiation. Nevertheless, the increase in microstrain, electrical resistivity and microhardness on irradiation indicates creation of lattice damages inside polycrystalline tungsten specimen. On the other hand, the thermal diffusivity has not change much on heavy ion irradiation. The induction of damages in metallic tungsten is mainly attributed to high electronic energy loss, which is 40 keV/nm in present case as obtained from SRIM program. Although, concomitant effect of nuclear losses on damage creation cannot be ignored. It is believed that the energy received by the electronic system is being transferred to the atomic system by electron-phonon coupling. Eventually, elastic nuclear collisions and the transfer of energy from electronic to atomic system via inelastic collision is leading to significant defect generation in tungsten lattice. [ABSTRACT FROM AUTHOR]

In response of swift heavy ion (100 MeV I9+) irradiation, the irradiation‐induced disordering in nonstoichiometric pyrochlore composition (Nd1.8Zr2.2O7.1) was compared to that of stoichiometric composition Nd2Zr2O7. Both compositions were prepared through auto gel‐combustion followed by sintering under the identical conditions. Systematic analysis of the compositions before and after irradiation was performed with X‐ray diffraction (XRD), Raman spectroscopy, and plane‐view high‐resolution transmission electron microscopy (HRTEM) techniques. Irradiation caused pyrochlore to amorphous phase transformation was observed in both compositions except the slower rate of amorphization in Nd1.8Zr2.2O7.1. The amorphization was achieved as a consequence of isolated disordered track overlapping at higher ion fluence with the estimated track diameter 2.73 ± 0.05 and 3.46 ± 0.30 nm for Nd1.8Zr2.2O7.1 and Nd2Zr2O7, respectively, employing the framework of single‐ion impact model to XRD results. HRTEM micrographs also revealed the less prevalence of irradiation‐induced amorphization in Nd1.8Zr2.2O7.1 with the observed irradiation‐induced modified track region composed of defect‐rich pyrochlore structure, anion‐deficient fluorite structure, and amorphous domains; with the diameter of 3.0 ± 1.0 nm and 5.0 ± 1.0 nm in Nd1.8Zr2.2O7.1 and Nd2Zr2O7, respectively. The preexisting anion‐deficient fluorite structure in Nd1.8Zr2.2O7.1 helps in its epitaxial growth as recovered structure from melted ion track during irradiation‐induced rapid cooling. [ABSTRACT FROM AUTHOR]

Research progress in the field of synthesis of graphene-like nanosheets has been expeditiously growing in the recent years because of their incredible properties in various fields offered by these two-dimensional nanostructures. Nano order thick graphitic flakes, one of the forms of graphene, can be used for many applications such as conductive inks, supercapacitors, nanofluids, gas sensing, etc. Synthesis of graphene flakes definitely the way to reach bulk quantity production. Preparation of stack layer graphene-like nanosheets from industrial waste carbon flake is important for scalable production at a low cost and societal uses. Our novel work surmised the fabrication of Nano order thick graphitic flakes from industrial waste using the modified hummer's method. The basic morphological characteristics have been examined by X Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Gas sensor was prepared by depositing a thin film on a figure-type interdicted electrode epoxy substrate. The sensing behavior was detected by monitoring the change in resistance after hydrogen gas exposure using a computer control indigenously developed hydrogen gas sensing unit. • This work presents novel synthesis of Nano order thick graphene-like nanosheets from industrial waste using hummer's method. • The qualitative and quantitative analysis of synthesize nanosheets have done by characterized physicochemical properties. • The synthesize nanosheets based chemiresistor type gas sensor was prepared and tested for hydrogen gas. • The sensor shows the faster response and higher sensitivity over a long period toward hydrogen gas at room temperature. [ABSTRACT FROM AUTHOR]

Series of Al3+ doped Gd 1.92 Ti 2-x O 7 :Eu 0.08 Al3+ x (where x = 0, 0.02, 0.04, 0.06, & 0.08), powdered samples had been successfully developed using the solid-state reaction strategy. The purity of the produced samples was confirmed using X-ray diffraction analysis, while through Raman spectroscopy analysis and deconvolution, it has been observed that high intensity vibrational bands exhibited a blue shift (from 312.3 to 313.9 cm−1 and 518.2–518.6 cm−1) upon the introduction of Al3+ substitution in the Gd 1.92 Eu 0.08 Ti 2 O 7 host lattice. Photoluminescence excitation spectra showed absorption in the ultraviolet & near-ultraviolet regions for Gd 1.92 Eu 0.08 Ti 2 O 7 , monitored at a wavelength of 588 nm. On the other hand, the Al3+ doped Gd 1.92 Eu 0.08 Ti 2 O 7 oxides exhibited distinct absorption bands in 250–500 wavelength region, in addition to the host excitation bands. Under 322 nm excitation, the Al3+ doped Gd 1.92 Eu 0.08 Ti 2 O 7 pyrochlore oxides displayed a dominant orange-reddish emission spike at 588 nm occurring due to 5D 0 →7F 1 transition, along with weak emission peaks at 612 nm originating from 5D 0 →7F 2 transition of trivalent europium ions. Similarly, under 394 nm excitation, the whole series exhibited analogous emission spikes, with the highly intense peak centered at 588 nm and weak band at 612 nm but in this case the emission intensity for all the peaks are relatively low as compared to when excited to 322 nm. The energy transfer processes and their relative possible reasons for concentration quenching above a Al3+ ion concentration of 2.0 mol% were discussed in detail. The optimized sample showed CIE chromaticity coordinates of (0.605, 0.392) under 322 nm excitation, indicating its positioning in the orange-reddish region. The CIE coordinates measured, depends on the emission profile under 322 nm excitation closely matched those of the economic phosphor Y 2 O 2 S:Eu3+ (x = 0.622 and y = 0.351). Overall, these results highlight the potential of Al3+ doped Gd 1.92 Eu 0.08 Ti 2 O 7 pyrochlore oxides as orange-reddish emitting components for luminescent devices. [ABSTRACT FROM AUTHOR]

Pyrochlore ceramics with chemical formula A 2 B 2 O 7 (A= rare earth, B= tetravalent metal) have extremely low thermal conductivities (κ) and are thought to be promising candidates for thermal barrier coatings (TBCs) applications. This study reports κ for nanocrystalline (nc) Gd 2 Ti 2 O 7 pyrochlore fabricated by spark plasma sintering followed by sintering at different temperatures to better understand their thermal properties. The structural analysis confirmed the synthesis of single-phase nc-Gd 2 Ti 2 O 7 pyrochlore. The thermal conductivity investigations displayed a systematic decrease in thermal conductivity from 1.6 Wm−1K−1 to 0.6 Wm−1K−1 for the sample sintered at a lower temperature due to high porosity. The value of the κ is found to decrease sublinearly (κ ∝ T-α, where 0 < α < 1) with temperature for all the nc-Gd 2 Ti 2 O 7 pyrochlore samples. DFT- GGA calculation exhibits that the nc-Gd 2 Ti 2 O 7 is a direct band gap at the Γ point of the Brillouin zone, and its value is increased with the sintering temperature. In addition, the effect of sintering temperature on the specific heat capacity (C p) is insignificant in nc-Gd 2 Ti 2 O 7 structures, as confirmed by the quasi-harmonic approximation. Theoretical and experimentally determined results are in good agreement, and values are compatible with the thermal insulation requirements for various applications. • The thermal conductivity (κ) decreases from 1.6 Wm-1K-1 to 0.6 Wm-1K-1 with lowering sintering temperature. • The thermal conductivity (κ) decreases similarly for the highly dense samples sintered at 1000 ℃ and 1200 ℃. • The κ value decreases sublinearly (κ ∝ T-α, where 0 < α < 1) with temperature for all the nc-Gd 2 Ti 2 O 7 pyrochlore samples. • DFT calculated specific heat capacity (C p) systematically increases with increasing measuring temperature. [ABSTRACT FROM AUTHOR]

Highlights: [•] Effect of volume fractions on change in the size of embedded silver nanoparticles. [•] Surface plasmon resonance study to understand the dipolar interactions. [•] Study provides data for the development of non-equilibrium thermodynamics. [ABSTRACT FROM AUTHOR]

Abstract: Organic nonlinear optical crystal l-asparaginium picrate was subjected to 100MeV Ag8+ ions and 100MeV Si8+ ions. The dielectric properties of the crystals were studied before and after irradiation from 100Hz to 5MHz at various temperatures (308K to 358K). A drastic increase in the dielectric constant is seen due to irradiation. The dielectric constant and dielectric loss increase with increasing irradiation fluence. The UV–vis spectra of the pristine and irradiated samples were recorded and quantified. There is a small shift in absorption edge towards lower wavelength for the irradiated crystals due to the decrease in bandgap of the material. The observed results are discussed in detail. [Copyright &y& Elsevier]

This article reviews the recent development in the understanding of the design parameters as well as mechanical properties and the radiation stability-based classification of the single-phase high entropy alloys (HEAs). Because of their excellent radiation tolerance, HEAs are proposed as the potential candidate for their application as a structural material in generation-IV nuclear reactors, where harsh environmental condition prevails. Theoretical calculation and experimental studies suggest that phase-stability and elemental distribution in the solid solution depend on the binary enthalpy of mixing, atomic size, electronegativity and magnetic nature of the elements. Energetic heavy ion irradiation investigations on the HEAs confirmed that the composition, chemical nature, number and size of alloying elements play an important role to determine their response to irradiation. Furthermore, irradiation stability at elevated temperatures also depends upon the incorporation of elements like Pd and Al in the solid solution. Phase stability, radiation-induced segregation (RIS) and bubble formation in HEAs are affected by both the irradiation temperature as well as the types of alloys and their microstructure. Finally, the improvement in structural stability in a high-temperature radiation environment and their applicability as structural materials in the nuclear reactor system have been reviewed. [ABSTRACT FROM AUTHOR]

Nano-composite Co 84 Zr 16 N (CZN) films were prepared by reactive co-sputter deposition. As-deposited CZN films have not shown any exchange bias effect. But annealed (390 K) and field cooled samples have shown exchange bias phenomena. The observed exchange bias is attributed to inter-cluster exchange coupling between ferromagnetic and antiferromagnetic nano-composite phase. High resolution transmission electron microscope study reveals that, the CZN films are composed of ordered and crystalline ferromagnetic Cobalt nano-clusters embedded in an antiferromagnetic matrix. X-ray diffraction confirms the poly-crystalline growth of the CZN films with a preferred fcc (622) phase formation. In-plane anisotropy of the exchange biased films was investigated by rotational magnetization curve, and the analysis shows that the magnetization reversal behaves according to the coherent rotation of the magnetic moment vector. Effectively, exchange bias effect in such single layer films could be attributed to co-existing antiferromagnetic and ferromagnetic phase within the single layer. Such single layer nano-composite films can be a possible alternative to the bilayer combination of antiferromagnetic/ferromagnetic exchange biased films and are ideally suited for spintronics and tunnel junction applications. [ABSTRACT FROM AUTHOR]

Abstract: Our long term objective is to study the swift heavy ion (SHI) irradiation effect on photoanode of dye-sensitized solar cell (DSSC) with the aim to investigate the stability of DSSC component in space irradiations and possibility of improvement in efficiency of DSSC due to ion induced effects in oxide layer. The DSSC photoanode consists of three layers viz; transparent conducting oxide (TCO), porous oxide with wide band gap and monolayer of dye molecule on top of corning glass substrate respectively. In the present study, procured radio frequency (RF) sputtered indium tin oxide (ITO) film on corning glass substrate were irradiated by SHI using 110MeV Ni8+ ions at different fluences ranging from 3.0×1011 ion/cm2 to 1.0×1014 ion/cm2. After irradiation significant changes have been observed in the structural, optical and electrical properties using X-ray diffraction (XRD), UV–Vis and Four Probe measurements, respectively. Overall there is 13% increase in optical transmittance which is favorable and moderate increase in sheet resistance from 8Ω/□ to 18Ω/□ which is still within acceptable limits for DSSC applications. [ABSTRACT FROM AUTHOR]