Combinatorial approach for ferroelectric material libraries prepared by liquid source misted chemical deposition method

*Department of Chemical and Biomolecular Engineering and Center for Ultramicrochemical Process Systems, and
^†Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Republic of Korea

Communicated by Gabor A. Somorjai, University of California, Berkeley, CA, November 24, 2006 (received for review August 24, 2006)

Abstract

Combinatorial approach for discovering novel functional materials in the huge diversity of chemical composition and processing conditions has become more important for breakthrough in thin film electronic and energy-conversion devices. The efficiency of combinatorial method depends on the preparation of a reliable high-density composition thin-film library. The physico-chemical properties of each sample on the library should be similar to those of the corresponding samples prepared by one-by-one conventional methods. We successfully developed the combinatorial liquid source misted chemical deposition (LSMCD) method and demonstrated its validity in screening the chemical composition of Bi_3.75La_xCe_0.25-xTi₃O₁₂ (BLCT) for high remanent polarization (P _r). LSMCD is a cheap promising combinatorial screening tool. It can control the composition up to ppm level and produce homogeneous multicomponent library. LSMCD method allows us to prepare BLCT thin-film library at the variation of 0.4 mol% of La. Maximum 2P _r is 35 μC/cm⁻² at x = 0.21. The intensity of (117) XRD peak is quantitatively related to 2P _r. Newly developed scanning piezoelectric deformation measurement for nano-sized samples using scanning probe microscope (SPM) is also found out to be reliable for determining the relative ranking of P _r value rapidly.

Footnotes

^‡To whom correspondence should be addressed. E-mail: siwoo{at}kaist.ac.kr
Author contributions: K.W.K. and S.I.W. designed research; K.W.K. and T.S.K. performed research; K.W.K., K.S.O., and Y.S.K. contributed new reagents/analytic tools; K.W.K., M.K.J., and S.I.W. analyzed data; and K.W.K. and S.I.W. wrote the paper.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/cgi/content/full/0610146104/DC1.
Abbreviations:

LSMCD,

liquid source misted chemical deposition;

BLT,

(Bi,La)4Ti3O12;

BCT,

Bi4-xCexTi3O12;

BLCT,

Bi3.75LaxCe0.25-xTi3O12;

P–E,

polarization-electric field;

SPM,

scanning probe microscope;

AFM,

atomic force microscope.
Freely available online through the PNAS open access option.