CuInS₂ quantum dots-based unipolar resistive switching for non-volatile memory applications

Recent advancements have established quantum dots (QDs) as a promising alternative to conventional bulk materials in the fabrication of nanoscale integrated electronic devices. The appeal of QDs lies in their amenability to low-temperature processes and solution-based methodologies, facilitating the construction of devices with enhanced versatility and efficiency. The ternary metal chalcogenide CuInS₂ QDs are one of the foremost, eco-friendly, and highly stable materials. In this study, CuInS₂ QDs are employed as a functional layer in a memristive device featuring an Al/CuInS₂/ITO configuration. The CuInS₂ QDs have been synthesized by a hot injection method and characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM) to reveal their structural features. The Al/CuInS₂/ITO device shows a unipolar resistive switching (RS) behaviour with a high on/off ratio of 10⁵. The switching parameters have been studied for 100 cycles of SET/RESET. The SET and RESET voltages are found to be 1.66 ± 0.25 V and 0.69 ± 0.17 V. The spatial variability of switching parameters in the Al/CuInS₂/ITO structure has also been studied for 9 different devices. The device also exhibits unipolar RS behaviour in the optimum temperature range of 0 °C to 50 °C. These outcomes demonstrate the impressive performance of CuInS₂ QDs, indicating their potential for future energy-efficient and large-scale non-volatile memory applications.