Dielectric properties of vacuum-deposited bismuth oxide films

The dielectric properties of bismuth oxide films prepared by vacuum deposition have been studied in the frequency range 0.1–10 kHz and the temperature range 90–298.5 K. The capacitances C_p and C_s and the loss factor show dependences on the frequency, temperature and aging of the samples. The loss factor exhibits a flat maximum in its temperature variation curve at about 170 K. Interfacial polarization, which is caused by the excess bismuth and by various defects and impurities, is thought to be the main relaxation mechanism operating in the low frequency region.