Design of Mixed-Dimensional QDs/MoS2/TiO2 Heterostructured Resistive Random-Access Memory with Interfacial Analog Switching Characteristics for Potential Neuromorphic Computing

Resistive random-access memory (RRAM) is one of the most promising candidates for next-generation nanoscale nonvolatile memory devices and neuromorphic computing applications. In this study, we developed a novel mixed-dimensional design for RRAM devices, incorporating zero-dimensional quantum dots (QDs), two-dimensional MoS2, and a TiO2 switching layer to achieve prominent interfacial switching behaviors. Compared with typical filamentary RRAM devices, the proposed heterostructure featured a light-sensitive QDs/MoS2 layer that allowed for bias-controllable resistive changes during the set and reset processes without abrupt switching. This was endowed by effective electron–hole pair separations upon excitation and the generation of a thin molybdenum oxide (MoOx) layer due to the accumulation of oxygen ions at the interface between MoS2 and TiO2. The ITO/QDs/MoS2/TiO2/Pt RRAM device exhibited an on/off ratio of 10 with improved endurance under 515 nm laser illumination and wavelength-dependent resistive switching behavior, making it useful for multilevel storage. Furthermore, the heterostructured device demonstrated synaptic characteristics with enhanced potentiation and depression nonlinearities and asymmetry factors, revealing its potential for future neuromorphic applications.