Photoinduced strain in ferroelectric-based cantilevers

Due to their large number of properties, such as switchable polarization, piezoelectricity or optical absorption, ferroelectrics are particularly promising in order to develop the next generation of electronic microdevices. Among these ferroelectrics, lead zirconium titanate (PZT) has been widely investigated for its high electromechanical properties and more recently for its light-induced deformation¹, commonly named photostriction, combining simultaneously bulk photovoltaic and converse piezoelectric effects². Although this phenomenon was discovered in multiple ferroelectrics materials these last decades³, the photostriction is not fully understood. In this work, the interplay between the electric polarization and the photoinduced strain is investigated in PZT epitaxial-based cantilevers. For this purpose, the resonance frequencies of the cantilevers and their deflection were studied under UV illumination, through electrical measurements and optical profilometry respectively. The results have shown that the sign of both the photoinduced shift of resonance frequency and photoinduced deflection strongly depend on the polarization state in the ferroelectric thin film.
¹S. M.,doi: 10.1002/aelm.201800709.
²C. P.,doi: 10.1103/PhysRevLett.116.247401.
³B. K.,doi: 10.1063/1.4905505.