The Effects of the Annealing Conditions on the Dielectric Properties of the Sol-Gel Derived MgNb₂O₆ Thin Films

Abstract

MgNb2O6, a well-known ceramic material with columbite crystal structure, has attracted much attention in microwave integrated circuits and optical applications due to its superior properties, such as its high dielectric constant and an optical band gap. In this work, transparent amorphous-MgNb2O6thin films were fabricated on ITO/glass substrates using the sol-gel method. The average optical transmission percentage in the visible range (λ=400–800 nm) is over 80% for all MgNb2O6/ITO/glass samples, while the optical band gap is estimated at ~4 eV. On the other hand, the dielectric properties of the MgNb2O6thin films were very sensitive to the annealing conditions. In this study, the dielectric constant of the films was calculated to be higher than 30 under a 100 kHz AC electric field. The effects of the annealing temperature and atmosphere on the dielectric properties of the MgNb2O6thin films were investigated.