Structures and electrical properties of Mn- and Co-doped lead-free ferroelectric K0.5Na0.5NbO3 films prepared by a chemical solution deposition method

The un-doped, 2mol% Mn- and 2mol% Co-doped K0.5Na0.5NbO3 (KNN) films were prepared by a chemical solution deposition method. The crystalline phase and surface morphologies of KNN films hardly changed after Mn- and Co-doping. X-ray photoelectron spectrocopy analysis indicates that the introduction of both Mn and Co promoted the formation of KNN perovskite structure, and the most Mn2+ and Co2+ ions were oxidized into high-valence ions during thermal process. As a result, the leakage current density of the KNN films was decreased and the electrical properties were enhanced after the doping. •The leakage current density of K0.5Na0.5NbO3 (KNN) films decreased after doping•The introduction of dopant promoted the formation of KNN perovskite structure•A portion of introduced doping ions became high-valent after heat-treatment