A study of the 160 MeV Ni7+swift heavy ion irradiation effect of defect creation and shifting of the phonon modes on MnxZn1–xO thin films

Abstract

Mn_xZn_1–xO thin films were successfully synthesized by the dip coating technique. The thin films were irradiated by Ni⁷⁺ swift heavy ions (SHI) with 1 × 10¹³ ions per cm² fluence, and their structural, electrical, Raman spectral and surface morphological properties were investigated. X-ray diffraction patterns confirmed the P6₃mc space groups, and the crystallite size increased after SHI irradiation, due to electron rearrangements. I–V studies revealed enhanced conductivity after Ni⁷⁺ SHI irradiation and showed the ohmic nature of the sample. The irradiation sensor efficiency and responsibility were calculated by using I–V data, which revealed impressive results. Photoluminescence (PL) measurements were performed to determine the evolution of defects and defect-annealing during ion irradiation; enhancement in the luminosity of pure and 5% Mn substituted ZnO thin films was observed. The presence of the Raman active strongest optical phonon mode of ZnO at 436.19 cm⁻¹ revealed that ZnO with hexagonal wurtzite structure supported the XRD results. Atomic force microscopy (AFM) images revealed the formation of nano-bunches on the surface and enhanced the surface roughness and skewness of the irradiated samples, due to coulombic interactions between electrons and ions.