Effects of 120 MeV Ag9+ swift heavy ion irradiation on the structural, optical and electrical properties of pristine and Ni doped BiFeO3 thin films grown by pulsed laser deposition

In this work, the effects of swift heavy ion (SHI) irradiation on the structure, morphology, optical and electrical properties of pristine and Ni-doped BiFeO3 thin films have been explored. The thin films with composition of BiFe1-xNixO3 (x = 0, 0.01, 0.03 and 0.05) were deposited on the n-type single crystal Si(100) substrates through pulsed laser deposition technique. Further, irradiation on the thin films was performed with 120 MeV Ag9+ ions at different ion fluences, i.e., 1 × 1013, 5 × 1013 and 1 × 1014 ions/cm2. To investigate the effects of SHI irradiation on the aforementioned properties, all the films have been characterized by various analytical techniques, such as X-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, UV-visible diffuse reflectance spectroscopy and two-probe resistivity setup. The effects of the irradiation on the crystal structure and phase of the thin films were analyzed by the XRD and Raman measurements, and it has been observed that irradiation tends to amorphize the thin films. A decrease in the band gap has been observed for the irradiated thin films with the increase of ion fluence. The current-voltage plots of all the unirradiated and irradiated thin films demonstrate the rectifying diode type characteristics.