Large piezoresponse of lead-free Bi0.5(Na0.85K0.15)0.5TiO3 thin film

0.85Bi0.5Na0.5TiO3–0.15Bi0.5K0.5TiO3 (BNKT15) lead-free thin films were prepared on Pt(111)/TiO2/SiO2/Si(100) substrates by the chemical solution deposition method. BNKT15 are MPB composition in the Bi0.5Na0.5TiO3–Bi0.5K0.5TiO3 (BNT–BKT) system. The maximum piezoelectric coefficient (d33,f) value of BNKT15 thin film is approximately 75 pm/V, which is comparable to that of polycrystalline PZT thin films. These results suggest that BNKT15 thin film can be used as an alternative for PZT films in piezoelectric micro-electromechanical systems.

► 0.85Bi0.5Na0.5TiO3-0.15Bi0.5K0.5TiO3 (BNKT15) lead-free thin films were prepared.
► BNKT15 are MPB composition in the BNKT system.
► Piezoelectric coefficient (d33,f) value of BNKT15 thin film is 75 pm/V.
► d33,f value of BNKT15 film is comparable to that of polycrystalline PZT thin films.
► BNKT15 thin film can be used as an alternative for PZT thin films.