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Low energy ion beam-induced nanoscale ripple patterns have attracted attention due to their use in various technological applications. Making defect free, highly regular, and low wavelength (∼30 nm) ripple patterns is still under investigation as ripple patterns forms over triangular features (elevations and depressions) that curtail their use in an application. In this work using 300 eV Ar+ ion beam, the topographic evolution of such triangular features at elevated temperature up to 500°C for ion fluences of 2×1018 to 1×1019 ions.cm−2 was examined. Triangular features remain intact well up to 200°C with a marginal decrease in the base angle. Above 300°C, triangular features start corrugating and, finally both triangular features and ripple vanished at 500°C. The experimental findings were compared using modified anisotropic Kuramoto-Sivanshinsky (AKS) equation by Loew and Bradley (LB) incorporating simultaneously diffusion coefficient and third order dispersion term. Temperature-induced effects are adequately replicated; dispersion produces the triangular features and diffusion help to grow it further. In experiment base angle and lateral length of the triangles decreases with increasing temperature, similar trend was observed in numerical simulations by varying the diffusion coefficient.

The bouncing dynamics of impacting water droplet on low energy ion beam produced superhydrophobic PTFE surfaces was investigated for the self-cleaning application. Ion beam with 300 eV and 800 eV energies was used to produce nanostructures on PTFE surfaces having the bouncing behaviour. The bouncing dynamics of water droplet was studied using dynamics parameters like spreading factor (β), contact time (tc), time of flight (ta) and number of bounces. The maximum spreading factor for the impact velocity of 0.5 m s−1 and 1.0 m s−1 was found to be 1.4 and 2.0, respectively for both 300 eV and 800 eV irradiated surfaces. The contact time of impacted droplet on 800 eV irradiated surface with 0.5 m s−1 velocity was found to be much lower (tc = 13.00 ms) than 300 eV ion irradiated surface (tc = 19.67 ms). Post impact bouncing number as high as 14 was found for 800 eV irradiated surface. Depending on ion energy and irradiation time the surface was converted from complete wetting to complete bouncing at low impact velocity of 0.5 m s−1 and from complete bouncing to partial bouncing at 1.0 m s−1. The self-cleaning property on 800 eV irradiated surface was successfully demonstrated using carbon powder.

Ion beam irradiation produced ripple nanopatterns on Si surface was used to produce a highly dense and sensitive SERS substrate for detecting Dichlorvos pesticide below the permissible limit. The wavelength of the ripple varied from 22 nm to 35 nm by changing ion beam energy from 200 eV to 500 eV. Highly regular nanoparticles arrays were produced down to 22 nm wavelength choosing the proper ion beam parameter and ripple orientation during deposition. The shape of deposited nanoparticles on ripple nanostructures changed from elongated to spherical upon increasing wavelength and amplitude of ripples at different ion energies. The optimization of SERS intensity was carried out using crystal violet dye which revealed that the maximum enhancement (enhancement factor ~107) occurred for the 300 eV irradiated substrate. The optimized substrate was used for detecting Dichlorvos up to 1 ppm level without using any binder molecule.

Modified alloy zincate (MAZ) is a surface-treatment process for depositing Zn on Al by galvanic displacement reaction prior to application of functional coatings. Two-step zincating i.e. double zincating (DZ) is a preferred technique in comparison to single zincating (SZ) because of imparting excellent adhesion of coatings on Al. Prior to second step of zincating during DZ, the single zincated Al substrate undergoes nitric dissolution. In this study, the intriguing role of this nitric acid etching on second step nucleation and growth of Zn has been investigated in detail. For this, time dependent Zn-nucleation and growth morphology on Al surface was monitored by AFM and FESEM examinations and revealed scattered but coarse nucleation during SZ; and finer nucleation along with uniform coverage of Zn during DZ. Post single zincating, nitric acid etch led to generation of micro/nanoporous Al surface as revealed by microscopic investigations. The porous Al surface along with trace amount of noble metals such as Cu and Fe was found to play significant role on Zn root growth into Al matrix and fine grain Zn deposit on top surface confirmed by cross-section FESEM analysis of focused ion beam (FIB) cut Zn/Al sample. Rutherford Backscattering Spectroscopy (RBS) was used as a non-destructive technique to estimate Zn film thickness and growth rate. The observed Zn nucleation and growth results were further substantiated by analyzing the open circuit potential (OCP) data during zincating. Difference in nucleation and growth pattern of Zn on Al surface during SZ and DZ was fundamentally understood with the help of classical nucleation theory and galvanic kinetics.