LANTHANUM AND 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 growth through self-assembly are studied. In this paper, we synthesize the lanthanum and niobium substituted Bi₄Ti₃O₁₂ nanostructures on Pt/Ti/SiO₂/Si substrates. The method we used here was spin coating precursors with a serious of concentration on the substrates and then annealing at 700°C or 750°C in the oxygen atmosphere to get the self-patterning nano particles. Scanning probe microscope (SPM), and x-ray diffraction (XRD) were used to detect the morphology and the crystalline structure of the nano particles. 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 is, the higher the excess of Bi element is needed to form the pure perovskite nanoparticles.

Keywords:

• Nanostructure
• La- and Nd-substituted Bi4Ti3O12
• self-assembly

PACS:

• 81.16.Dn
• 77.80.−e
• 81.07.−b

Acknowledgment

This work was supported by the National Science Foundation of China (No 90207027, 90401014), the 973 Project of MOST (2002CB613303) of China, and Jiangsu Natural Science Foundation (No. BK 2002410, BK2004084).