X-ray diffraction, atomic force microscopy and raman spectroscopy studies of microstructure of BiFeO3 thin films on Pt/Ti/SiO2/Si (111) substrates

Abstract

A set of BiFeO3 (BFO) thin films with different thicknesses deposited on Pt/Ti/SiO2/Si (111) substrates and LaNiO3 (LNO)-buffered Pt/Ti/SiO2/Si (111) substrates using a radio-frequency magnetron sputtering technique was studied by X-ray diffraction (XRD), atomic force microscopy (AFM) and Raman spectroscopy. The XRD patterns demostrated that all BFO thin films were polycrystalline with a distorted rhombohedral structure even though there were distinct changes in the main peak positions and intensities. The AFM topography images also clearly illustrated the different surface profiles of these thin films. The grain size of thin films deposited on LNO-buffered subtrates was greatly decreased compared to that of thin films deposited directly on Pt/Ti/SiO2/Si (111) substrates. Raman-active modes, which can be classified as 4A 1 and 9E modes, have been observed in the Raman spectra of the BFO thin films. Variations in the Raman shift and bandwidth of different BFO thin films reveal the influence of the thin film and buffer layer thicknesses on the film microsturcture.