Phase transformation of CdSe nanocrystals at high fluence irradiation of 120 MeV swift Ni10+ and Ag7+ ions – X-ray diffraction and Raman spectral analysis

Abstract

In this work, cadmium selenide (CdSe) nanocrystals have been chemically synthesized and subsequently characterized by SEM, XRD and Raman Study. XRD pattern of pristine CdSe nanocrystals show cubic lattice structure with average particle size of 34 nm approximately. CdSe nanocrystals have been irradiated by 120 MeV swift Ni10+ and Ag7+ heavy ions (SHI) at different ion fluences of 1 × 1011, 1 × 1012 and 3 × 1013 ions/cm2. XRD patterns reveal a structural phase transformation from cubic to hexagonal phase in the SHI irradiated CdSe nanocrystals at highest fluence in both the cases of Ni10+ and Ag7+ ions. Since the deposited energy loss of Ni10+ and Ag7+ ions is different, the evolution of hexagonal phase with the ion fluences is also different. Here, a comparative analysis of the effect of Ni10+ and Ag7+ ion on CdSe nanocrystals have been studied using Garvie and Nicholson model to understand the mechanism of the phase transformation. Further, the effect of both the swift ion on the structural properties of CdSe nanocrystals has also been studied with the help of Raman Spectral analysis.