Resistive switching and photovoltaic response characteristics for the BaTiO3/Nb:SrTiO3 heterostructure

Recently, perovskite compounds with ABX3 structures have been attracting increasing attention because of their excellent properties and their potential for applications in fields such as optoelectronics and memory devices. In this Letter, we introduce a BaTiO3/Nb:SrTiO3 (BTO/NSTO) heterostructure that displays both resistive switching and photovoltaic response characteristics. As a dual-function device, our heterostructure device not only exhibits bipolar resistive switching behavior with a switching ratio of up to 103 without any forming process but also shows a tunable photovoltage effect with an open-circuit voltage (Voc) of approximately 0.38 V. In addition, a high-resistance state and a low-resistance state of the device can be modulated by light illumination. This photo-modulation mechanism is revealed and shows that resistive switching can be attributed to migration of photogenerated carriers and charge trapping/detrapping caused by ferroelectric polarization reversal, which changes depletion layer characteristics at the BTO/NSTO interface. This work may help to provide an understanding of multifunctional characteristics of the BTO/NSTO heterostructure and will pave the way toward practical applications of this heterostructure in memory and optoelectronic devices.