Resistive switching memory device with metal‐oxide quantum dots on a graphene layer

We demonstrate a one diode–one resistor (1D–1R) type resistive switching memory device consisting of single layered metal‐oxide quantum dots (QDs) and a vertically inserted graphene layer between the SiO 2 layers on an n + ‐Si substrate. Mono‐layered graphene on the bottom SiO 2 layer with a thickness of 50 nm was capped by a 5 nm thick SiO 2 top barrier layer deposited by using an ultra‐high vacuum sputter. The In 2 O 3 QDs layer embedded in the 50 nm thick biphenyltetracarboxylic dianhydride‐phenylenediamine polymer layer was formed by a curing process using polyamic acid at 400 °C for 1 h. The current values of the high and low resistance states for this 1D–1R device were measured to be about 3.32 × 10 −9 and 5.54 × 10 −9  A at a read bias of 1 V, respectively. The ratio of each resistance after applying sweeping bias from +8 to −8 V and from −8 to +8 V appeared to be about 0.59 at 1 V. This resistance switching could have originated from the migration of the O −2 ions by the redox chemical reaction in the polyimide and carrier charging effect of the QDs. This hybrid memory structure with In 2 O 3 QDs and graphene layer has a strong possibility for application in next generation nonvolatile memory devices.