Biography
Biography: Roman Korobko
Abstract
Electrochemical resistive switches operating on ionic carriers, sometimes named memristors, may revolutionize the future electronics as the next generation building blocks of non-volatile memory and neuromorphic computing replacing electronically operated classic transistor structures. Despite an extensive research performed on solid oxide materials, the technology is still immature. Therefore, the exploration in the direction of understanding the mechanisms and adaptation of novel materials systems is ongoing. In this presentation, we show a study of memristive properties of Ce0.8Gd0.2O1.9/VO2 thin film system (Gd-doped ceria (GDC), and V4+ vanadia). Ceria is a well-studied ionic conductor that tolerates high percentage of mobile oxygen vacancies. Vanadia, as VO2 is famous for its metal-insulator transition, an ability to switch the resistance by several orders of magnitude by change of temperature, electromagnetic fields or mechanical strain beyond a sufficient transition level. Furthermore, ceria is a wide bandgap (~3 eV) and vanadia is a narrow bandgap n-type semiconductor (0.7 eV). Combination of these materials in one device seems incompatible for the conventional electronic materials strategy due to the dissimilar electric/dielectric properties. We show that integrating both oxides in the double layer device yields to synergetic memristive results, which are uncharacteristic neither for GDC nor for VO2 as oxide constituents. It was experimentally found that the conduction and the resistive switching are governed by the mass transport kinetics, which is a function of the applied voltage, the electric field and the voltage application rate. We suppose that the field-induced transport of oxygen vacancies to and from the ceria-vanadia interface modifies the electrically variable energy barrier, which tunability is responsible for the enhanced memristance effect.
