“…Negative differential resistance (NDR), characterized by a decrease in current with increasing voltage, has attracted tremendous attention and has been regarded as an important element for nanoelectronic applications in low power memory, high frequency oscillators, and logic circuit applications. − Typically, NDR can be achieved via resonant tunnelling heterostructures with a system composed of double potential barriers and one potential well. , NDR behavior has also been observed in sandwiched membranes, which was normally attributed to charge-carrier trapping/detrapping by defects. , Here, we observed an intrinsic and pronounced room-temperature NDR effect with relatively small-size (∼30 μm) perovskite MP junctions, whereas the NDR behavior disappeared for large (∼80 μm) perovskite MP junctions, indicating a mechanism different from that in the previous literature. A model based on ion migration and enhanced carrier recombination in perovskites was developed to illustrate the size-dependent NDR behavior of the perovskites.…”