Transient carrier transport and rearrangement of space charge layers under the bias applied to ferroelectric M/PZT/M structures

A drift-diffusion model of unsteady carrier transport in M/PZT/M structure is proposed to account for the formation of the current peak in the current-voltage curves, which is not caused by the domain switching and observed only when the bias and polarization directions coincide. In the model, electrons generated by oxygen vacancies are trapped by titanium deep centers at room temperature and can move by hopping between titanium atoms in the electric field. The polarization is constant across the film thickness while it is zero within defective layers near the contacts. It is shown that a pronounced current peak is formed when an accumulated space-charge layer appears near one of the contacts under the action of the polarization and this effect is purely unstationary.