Modified structural, surface morphological and optical studies of Li3+ swift heavy ion irradiation on zinc oxide nanoparticles

Abstract

Nanoparticles of ZnO were synthesized by a co-precipitation method. The ZnO samples were irradiated by Li³⁺ swift heavy ions (SHI) with fluences of 5 × 10¹¹ and 1 × 10¹³ ions per cm², constant current of 1 particle nano ampere (PNA) and Li³⁺ ion energy of 50 MeV. Structural parameters of pristine and SHI-irradiated ZnO nanoparticles were investigated by XRD. It was explicitly confirmed by XRD data that pristine and SHI-irradiated ZnO samples show wurtzite structures. The particle sizes of pristine and SHI-irradiated ZnO samples were estimated using XRD data and found to be in the range of 20 nm to 22 nm. SEM images show that the pristine sample has a spherical shape, whereas the ZnO sample SHI-irradiated with 5 × 10¹¹ ions per cm² fluence exhibits enlargement in grain size, and the sample irradiated with 1 × 10¹³ ions per cm² fluence has a rod-like structure. EDAX was employed to investigate the elemental composition of the materials. Raman spectra show phonon interaction and vibration bands in the materials at 438.69 cm⁻¹ and 435.95 cm⁻¹ due to ZnO bonding. Atomic force microscopic (AFM) studies evince enhancement in roughness and track formations after SHI irradiation of ZnO samples as compared to the pristine counterpart. The UV-vis spectroscopy results show a decreased energy band gap (red shift) with enhanced Li³⁺ swift heavy ion irradiation on the ZnO nanoparticles.