High-energy 120 MeV Au9+ ion beam-induced modifications and evaluation of craters in surface morphology of SnO2 and TiO2 nanocomposite thin films

Effects of Heavy Ion Irradiation on the Thermoelectric Properties of In2(Te1-xSex)3 Thin Films

Ion irradiation is an exceptionally effective approach to induce controlled surface modification/defects in semiconducting thin films. In this investigation, ion-irradiated Se-Te-based compounds exhibit electrical transport properties that greatly favor the transformation of waste heat into electricity. Enhancements of both the Seebeck coefficient (S) and the power factor (PF) of In₂(Te_0.98Se_0.02)₃ films under 120 MeV Ni⁹⁺ ion irradiation were examined. The maximum S value of the pristine film was about ~221 µVK^-1. A significantly higher S value of about ~427 µVK^-1 was obtained following irradiation at 1 × 10¹³ ions/cm². The observed S values suggest the n-type conductivity of these films, in agreement with Hall measurements. Additionally, Ni ion irradiation increased the PF from ~1.23 to 4.91 µW/K²m, demonstrating that the irradiated films outperformed the pristine samples. This enhancement in the TE performance of the In₂(Te_0.98Se_0.02)₃ system is elucidated by irradiation-induced effects that are revealed by structural and morphological studies.

Phase transformation and enhanced blue photoluminescence of zirconium oxide poly-crystalline thin film induced by Ni ion beam irradiation

Swift heavy ions (SHI) irradiation of Nickel (Ni) beam with different ions fluence bring the modifications in the functional properties of radio frequency (RF) grown zirconium oxide (ZrO₂) nanocrystalline thin films. X-ray diffraction analysis affirms the monoclinic to tetragonal phase transformation and diminishing of peak at higher fluence 1 × 10¹⁴ and 2 × 10¹⁴ ions/cm² induced by electronic excitation caused by SHI. Zirconium oxide thin films exhibit the same thickness (195 nm) of virgin and irradiated samples and whereas the nanocrystalline thin films have the elemental composition in proper stoichiometry (1:2) as analyzed by rutherford backscattering spectroscopy (RBS). Photoluminescence measurements confirm the blue emission of virgin and irradiated sample recorded at excitation wavelength 270 to 310 nm. The intensity of obtained emission bands varies with fluence which is interpreted in terms of generation and annihilation of defect centers. The characteristic A_g and B_g Raman modes of monoclinic and tetragonal ZrO₂ are obtained at different positions. Moreover, the nanocrystalline ZrO₂ thin films exhibits the most prominent absorption phenomenon in the visible range and the irradiation cause significant decrease in band gap to 3.69 eV compare to the virgin ZrO₂ sample (3.86 eV). XPS analysis indicates the shifting of the core levels Zr 3d and O 1s towards higher binding energy and spin—orbit splitting of different states. The findings in this research justify that the irradiated thin films can be a potential candidate for designing of new materials, intense radiation environments, nuclear reactors, nuclear waste systems, clean energy sources.

Catalytic Effect of Facile Synthesized TiH1.971 Nanoparticles on the Hydrogen Storage Properties of MgH2

Catalytic doping plays an important role in enhancing the hydrogen storage performance of MgH₂, while finding an efficient and reversible catalyst remains to be a great challenge in enhancing the de/rehydrogenation properties of MgH₂. Herein, a bidirectional nano-TiH_1.971 catalyst was prepared by a wet chemical ball milling method and its effect on hydrogen storage properties of MgH₂ was studied. The results showed that all the TiH_1.971 nanoparticles were effective in improving the de/rehydrogenation kinetics of MgH₂. The MgH₂ composites doped with TiH_1.971 could desorb 6.5 wt % H₂ in 8 min at 300 °C, while the pure MgH₂ only released 0.3 wt % H₂ in 8 min and 1.5 wt % H₂ even in 50 min. It was found that the smaller the size of the TiH_1.971 particles, the better was the catalytic effect in promoting the performance of MgH₂. Besides, the catalyst concentration also played an important role and the 5 wt %-c-TiH_1.971 modified system was found to have the best hydrogen storage performance. Interestingly, a significant hydrogen absorption amount of 4.60 wt % H₂ was evidenced for the 5 wt %-c-TiH_1.971 doped MgH₂ within 10 min at 125 °C, while MgH₂ absorbed only 4.11 wt% hydrogen within the same time at 250 °C. The XRD results demonstrated that the TiH_1.971 remained stable in cycling and could serve as an active site for hydrogen transportation, which contributed to the significant improvement of the hydrogen storage properties of MgH₂.