Transparent and Unipolar Nonvolatile Memory Using 2D Vertically Stacked Layered Double Hydroxide

Abstract Various 2D materials have received considerable attention as emerging nanoscale materials for low‐power and high‐performance electronic and optoelectronic device applications. Among these, layered double hydroxide (LDH)‐based nanocomposites are promising materials because of their structural diversity and electronic functionality, which are suitable for photocatalysts, catalytic supports, and charge storage. Here, three Al‐based LDHs using different divalent cations (Zn²⁺, Ni²⁺, and Co²⁺) are synthesized, and their electrical characteristics are investigated in the form of a two‐terminal Pt/Al‐based LDHs/fluorine‐doped tin oxide junction structure. Only the ZnAl‐LDH junction exhibits a distinct unipolar switching behavior with an ON–OFF ratio of ≈10³ and transmittance of ≈87%; the other junctions (NiAl‐ and CoAl‐LDHs) do not exhibit switching and possess relatively low transparency. This difference is attributed to the relatively vertically stacked ZnAl‐LDH layer, which enables the formation of a switching filament through the vertical 2D layer and enhances transparency. The ZnAl‐LDH junction has a relatively low trap energy (E_t) of ≈0.1 eV that can decrease the SET voltage as the temperature increases, which can be understood by trap‐assisted space‐charge‐limited conduction with thermal‐assisted electron excitation. This study sheds light on the potential use of transparent and self‐organized vertical stacked ZnAl‐LDH materials as resistive switching devices.