Light-controlled resistive switching in laser-assisted annealed Ba0.8Sr0.2TiO3 thin films

In this work, Ba0.8Sr0.2TiO3 (BST)/ITO structures were grown on glass substrate and laser assisted annealing (LAA) was performed to promote the crystallization of BST. Atomic force microscopy and X-ray diffraction studies confirm the crack free and polycrystalline perovskite phase of BST. White light controlled resistive switching (RS) effect in Au/BST/ITO device is investigated. The device displays the electroforming-free bipolar RS characteristics and are explained by the modulationof the width and height of barrier at the BST/ITO interface via ferroelectric polarization. Moreover, the RS effect is signifi- cantly improved under white light illumination compared to that in the dark. The enhanced RS and photovoltaic effects are explained by considering depolarization field and charge distribution at the interface. The devices exhibit stable retention characteristics with low currents (mA), which make them attractive for non volatile memory devices.

Acknowledgments This study has been partially funded by: (i) Project PEST-C/FIS/UI0607/2011 founded by Portuguese Foundation for Science and Technology (FCT); (ii) European COST Action MP1308-TO-BE. The authors J.P.B.S., K.C.S., and K.K. are grateful for financial support through the FCT Grants SFRH/BPD/92896/2013, SFRH/BPD/68489/2010, and SFRH/ BPD/87215/2012, respectively. The authors would also like to thank Engineer Jos e Santos for technical support at Thin Films Laboratory.