Enhanced piezoelectric response from barium strontium titanate multilayer films

Multilayered and homogeneous thin films of BaxSr1-xTiO3 (BST) were grown on Pt-coated Si substrates via metal-organic solution deposition. The multilayer 220 nm thick BST heterostructure consisted of Ba0.60Sr0.40TiO3, Ba0.75Sr0.25TiO3, and Ba0.90Sr0.10TiO3. A single composition 220 nm thick Ba0.60Sr0.40TiO3 was also grown for comparison. The piezoelectric properties were measured using piezoresponse force microscopy. There is approximately a 50% improvement in the piezoelectric response of the multilayered heterostructure compared to the homogeneous sample, with some spatial inhomogeneity. This enhancement can be attributed to the internal potential that arises from the polarization gradient and the commensurate built-in strain in the multilayer sample. (c) 2008 American Institute of Physics.