Ultrahigh stress response and storage properties in a single CdS nanobelt-based flexible device for erasable nonvolatile stress sensor and memory
Here, we demonstrate a single CdS nanobelt with quantities of stacking faults, synthesized by a thermal evaporation method, can show a giant stress-response to compressive and tensile strains with an excellent sensitivity, responsivity, and response and recovery speed. After being removed strains, more importantly, the stress can trigger a high resistance state (HRS), indicative of a nonvolatile stress sensing and memory effect. Moreover, the stress-induced HRS can be back to initial low resistance state (LRS) after subsequently being applied a relatively large bias, suggestive of a bias-erasing effect. In nanostructures, quantities of stacking faults, served as trap centers, can capture and store charges. Therefore, the bulk structure defects play a crucial role in superior stress sensor accompanied with erasable nonvolatile memory effect. Compressive strain can cause the height of trap barrier to decrease, and contrarily tensile strain can trigger it to increase. Therefore, the conductance of CdS nanobelt regularly increases with increase in compressive strain. On the contrary, it decreases with increase in tensile strain, showing a strain dependence of conductance. After being removed compressive or tensile strains, in addition, the total number of electrons localized in traps is both reduced, and correspondingly the conductance decreases, showing a nonvolatile stress-writing HRS memory effect. Subsequently, charges can be injected into traps at a relatively large bias, resulting into a recovery of LRS, namely erasable effect. Regarding a superior stress-switching accompanied with stress-writing and bias-erasing memory, multi-defect CdS nanostructure has a tremendous potential in nonvolatile stress sensor and memory application.