Chlorine-passivation of ozone-treated SnO2 thin films: Occurrence of oxygen vacancies to manipulate conducting states and bipolarities in resistive switching

Abstract

Highly conductive SnO2 thin films are of interest in transparent conducting electrodes for displays and n-type transport layer for perovskite solar cells. We fabricated SnO2 thin films by spin coating with ozone exposure. This process compensates for the oxygen vacancy states of the films. A local current–voltage measurement by conductive atomic force microscopy revealed the conducting characteristics of the films. Under different ambient conditions, the films exhibited an exotic cycling bipolarity in their resistive switching phenomena, which is likely dependent on the distinct formation of the oxygen vacancies. After application of a chlorine-based surface coating, the SnO2 surface showed an identical bipolar resistive switching. In particular, the chlorine-passivation was simple and robust to control oxygen vacancies and conducting states, which yields a low power operation below 1–2 V and a huge difference between low- and high-resistant states of a 108–1010 order of magnitude. Ozone-treated and chlorine-passivated oxide beyond SnO2 will provide guidance for optoelectronic device improvement. © 2021