Zirconia quantum dots for a nonvolatile resistive random access memory device

We propose a nonvolatile resistive random access memory device by employing nanodispersion of zirconia (ZrO2) quantum dots (QDs) for the formation of an active layer. The memory devices comprising a typical sandwich structure of Ag (top)/ZrO2 (active layer)/Ti (bottom) are fabricated using a facile spin-coating method. The optimized device exhibits a high resistance state/low resistance state resistance difference (about 10 Ω), a good cycle performance (the number of cycles larger than 100), and a relatively low conversion current (about 1 µA). Atomic force microscopy and scanning electron microscope are used to observe the surface morphology and stacking state of the ZrO2 active layer. Experimental results show that the ZrO2 active layer is stacked compactly and has a low roughness (Ra=4.49 nm) due to the uniform distribution of the ZrO2 QDs. The conductive mechanism of the Ag/ZrO2/Ti device is analyzed and studied, and the conductive filaments of Ag ions and oxygen vacancies are focused on to clarify the resistive switching memory behavior. This study offers a facile approach of memristors for future electronic applications.