C-AFM study on multi - resistive switching modes observed in metal–organic frameworks thin films

MOF‐Based Sustainable Memory Devices

“…Regarding the time that the recorded information is stored on a non‐volatile ReRAM device (retention) when the power is off, several articles [ 65–67,71,72 ] reported values from 10 4 to 10 5 s. As expected, additional electronic and AFM experiments confirmed the structural changes of MOF, while giving reason to believe that retention can be much higher.…”

“…[8] When a set voltage (V set ) is applied, this layer reacts structurally and, hence, electronically, changing its conductivity in a reversible way. [61] Surprisingly, MOFs can be successfully used as such active layers, [64][65][66][67][68][69][70][71][72][73][74][75][76] with no performance loss, and even sometimes outperforming the commercial counterparts (Table 2).…”

“…[27] Thus, the rate for recording/reading the information (≈10 ns), achieved by commercial memristive devices (Table 2), is to be expected for MOFs in the near future. Concerning the modification area, as shown by a number of works, [65,66,72] the current modification of the structure with a resolution of up to 10 nm (limited by the AFM tip diameter) is possible. However, the MOF surface roughness (>50 nm for general MOF thin films) and their structural defects can extend this area and, hence, decrease the storage density.…”

“…Nevertheless, there is not enough experimental data confirming irreversible structural changes of MOFs after prolonged switching. However, based on the proposed switching mechanisms for ReRAM, involving the formation of conducting filaments inside the framework itself [66,67,69,70,73] or through the pores, [64,65,68,71,72,74,75] one can expect the integrity of some MOF structure during the prolonged switching. [61,62] In addition to the operation characteristics of MOFs as active elements of the memory devices (Table 2), their production should be integrated with existing industrial approaches such as thin-film synthesis and vapor deposition.…”

“…If the compound [118] mer-[Ru(2(phenylazo)pyridine) 3 ](PF 6 ) 2 demonstrates the highest performance, it is also the one using the metal with the highest supply risk (Ruthenium). The common compounds [65][66][67][68][69][70][71][72][73][74][75][76] like MIL-53, ZIF series, and HKUST are synthesized with abundant metals (Al, Cu, Zn, etc.) which reduces the supply risk (Figure 13g,h) and also the solicitation of the reserves, of the production as well as the CO 2 footprint since they are primary product, unlike Ru (secondary product of Platinum).…”