Selecting Steady and Transient Photocurrent Response in BaTiO3 Films

TL;DR

This study investigates how contact configurations influence the steady and transient photocurrent responses in BaTiO3 ferroelectric films, revealing that Schottky barriers control the photoresponse and offering insights for memory device applications.

Contribution

It demonstrates that Schottky barrier height at electrodes determines steady versus transient photocurrent behavior in BaTiO3 films, providing a method to tune photoresponse for memory applications.

Findings

Photocurrent direction is governed by the depolarizing field, not imprint.

Steady photocurrents occur with imprint, transient without.

Schottky barrier height controls the transition between steady and transient responses.

Abstract

The ferroelectric polarization and short-circuit photocurrent in BaTiO3 thin films have been studied for different contact configurations that allow to measure the photoresponse and polarization under the presence of large or negligible imprint field. It is found that in all cases, the direction of the photocurrent is dictated by the depolarizing field and ultimately by the film polarization, with a negligible contribution of the imprint electric field. However, dramatic differences are found in their time-dependent photoresponse. Whereas in presence of imprint, steady photocurrents are observed under suitable illumination, transient photocurrents are generated in absence of imprint. It is argued that this distinct behavior is determined by the different Schottky barrier height at electrodes which thus offers a simple way to tune the film photoresponse. These findings could be exploited for electro-optic read-out and writing of ferroelectric memories.