Fabrication and properties of ge-doped (Bi,Nd)4Ti3O12 thin films by chemical solution deposition

Nd- and Ge-codoped Bi4Ti3O12 thin films have been fabricated by chemical solution deposition. The effects of Ge doping in (Bi,Nd)(4)Ti3O12 on microstructural and ferroelectric properties were investigated for the development of low-temperature fabrication of ferroelectric Bi4Ti12-based thin films. Bi3.35Nd0.75Ti3-xGexO12 [0 less than or equal to x less than or equal to 0.5] thin films were found to crystallize into the Bi4Ti3O12 phase above 600degreesC without forming any second phase. The crystal orientation and surface morphology of the synthesized films strongly depended on the Ge content of Bi3.35Nd0.75Ti3-xGexO12. Among various compositions of Bi3.35Nd0.75Ti3-xGexO12, Bi3.35Nd0.75Ti2.9Ge0.1O12 thin films showed excellent surface morphology and ferroelectricity regardless of the processing temperature. Furthermore, the doping of Ge below x = 0.1 was found to be effective in improving the ferroelectric properties of the low-temperature-processed films. The P-r values of Bi3.35Nd0.75Ti3-xGexO12 thin films with the optimum Ge content prepared at 600degreesC were above 15 muC/cm(2) and equal to those of the films crystallized at 700degreesC.