Origin of Abnormal Dielectric Behavior and Chemical States in Amorphous CaCu3Ti4O12 Thin Films on a Flexible Polymer Substrate

High dielectric constant thin films processable at nearly room temperature have been demanded for various flexible electronic devices. Here, we explore the origin of abnormal dielectric behavior of amorphous CaCu3­Ti4O12 (CCTO) thin films having an exceptionally high dielectric constant, in conjunction with chemical states and unusual ferroelectricity in the amorphous state. As an optimal example, the amorphous CCTO film sputtered at room temperature under an oxygen partial pressure of 3.6 mTorr exhibits a dielectric constant of ∼192 and a dielectric loss of