Neodymium substituted Bi₄Ti₃O₁₂ nanostructures through self-assembly

Abstract

For the sake of fabricating the ultrahigh density ultralarge scale integration (ULSI) memory chips, the ferroelectric nanostructures fabricated through self-assembly are studied. In this paper, we synthesized the neodymium substituted Bi₄Ti₃O₁₂ nanostructures on Pt/Ti/SiO₂/Si substrates. The method we used here was spin coating precursors with a series of different concentrations on the substrates and then annealing at 750 °C in the oxygen atmosphere to get the self-patterning nanoparticles. In order to avoid the influence of the Pt/Ti/SiO₂/Si substrates to the largest extent, the substrates were annealed first for different time in oxygen atmosphere to select appropriate conditions. Scanning probe microscope, and X-ray diffraction were used to detect the morphology and the crystalline structure of the nanoparticles respectively. The well-separated Bi_3.15Nd_0.85Ti₃O₁₂ particles have a typical lateral size about 100–150 nm and height about 20–25 nm. XRD reveals pyrochlore phase in the low concentration samples. The lower the precursor’s concentration, the higher the excess of Bi element is needed to form the pure perovskite nanoparticles.