Login / Signup

Large Electromechanical Response in a Polycrystalline Alkali-Deficient (K,Na)NbO 3 Thin Film on Silicon.

Moaz WaqarJianwei ChaiLai Mun WongPoh Chong LimShuting ChenWeng Heng LiewShijie WangJingsheng ChenQian HeKui YaoJohn Wang
Published in: Nano letters (2023)
The demand for large electromechanical performance in lead-free polycrystalline piezoelectric thin films is driven by the need for compact, high-performance microelectromechanical systems (MEMS) based devices operating at low voltages. Here we significantly enhance the electromechanical response in a polycrystalline lead-free oxide thin film by utilizing lattice-defect-induced structural inhomogeneities. Unlike prior observations in mismatched epitaxial films with limited low-frequency enhancements, we achieve large electromechanical strain in a polycrystalline (K,Na)NbO 3 film integrated on silicon. This is achieved by inducing self-assembled Nb-rich planar faults with a nonstoichiometric composition. The film exhibits an effective piezoelectric coefficient of 565 pm V -1 at 1 kHz, surpassing those of lead-based counterparts. Notably, lattice defect growth is substrate-independent, and the large electromechanical response is extended to even higher frequencies in a polycrystalline film. Improved properties arise from unique lattice defect morphology and frequency-dependent relaxation behavior, offering a new route to remarkable electromechanical response in polycrystalline thin films.
Keyphrases
  • room temperature
  • computed tomography
  • magnetic resonance imaging
  • magnetic resonance
  • air pollution
  • heavy metals
  • water soluble
  • wild type