Digital to analog resistive switching transition induced by graphene buffer layer in strontium titanate based devices

Tao Wan; Bo Qu; Haiwei Du; Xi Lin; Qianru Lin; Da-Wei Wang; Claudio Cazorla; Sean Li; Sidong Liu; Dewei Chu

doi:10.1016/j.jcis.2017.10.113

Digital to analog resistive switching transition induced by graphene buffer layer in strontium titanate based devices

J Colloid Interface Sci. 2018 Feb 15:512:767-774. doi: 10.1016/j.jcis.2017.10.113. Epub 2017 Oct 31.

Authors

Tao Wan¹, Bo Qu¹, Haiwei Du¹, Xi Lin¹, Qianru Lin¹, Da-Wei Wang², Claudio Cazorla³, Sean Li¹, Sidong Liu⁴, Dewei Chu⁵

Affiliations

¹ School of Materials Science and Engineering, The University of New South Wales, Sydney 2052, Australia.
² School of Chemical Engineering, The University of New South Wales, Australia.
³ School of Materials Science and Engineering, The University of New South Wales, Sydney 2052, Australia. Electronic address: c.cazorla@unsw.edu.au.
⁴ Sydney Medical School, The University of Sydney, Australia. Electronic address: sidong.liu@sydney.edu.au.
⁵ School of Materials Science and Engineering, The University of New South Wales, Sydney 2052, Australia. Electronic address: d.chu@unsw.edu.au.

PMID: 29112927
DOI: 10.1016/j.jcis.2017.10.113

Abstract

Resistive switching behaviour can be classified into digital and analog switching based on its abrupt and gradual resistance change characteristics. Realizing the transition from digital to analog switching in the same device is essential for understanding and controlling the performance of the devices with various switching mechanisms. Here, we investigate the resistive switching in a device made with strontium titanate (SrTiO₃) nanoparticles using X-ray diffractometry, scanning electron microscopy, Raman spectroscopy, and direct electrical measurements. It is found that the well-known rupture/formation of Ag filaments is responsible for the digital switching in the device with Ag as the top electrode. To modulate the switching performance, we insert a reduced graphene oxide layer between SrTiO₃ and the bottom FTO electrode owing to its good barrier property for the diffusion of Ag ions and high out-of-plane resistance. In this case, resistive switching is changed from digital to analog as determined by the modulation of interfacial resistance under applied voltage. Based on that controllable resistance, potentiation and depression behaviours are implemented as well. This study opens up new ways for the design of multifunctional devices which are promising for memory and neuromorphic computing applications.

Keywords: Analog resistive switching; Digital resistive switching; Reduced graphene oxide; SrTiO(3).