Gate‐Deterministic Remote Doping Enables Highly Retentive Graphene‐MXene Hybrid Memory Devices on Plastic
Seongchan Kim, Sae Byeok Jo, Jihyun Kim, Dongjoon Rhee, Yoon Young Choi, Do Hwan Kim, Joohoon Kang, Jeong Ho Cho
Abstract
Abstract In this work, a highly retentive and synaptic‐functional transistor memory device architecture based on the gate‐deterministic remote doping of graphene via surface‐oxidized Ti 3 C 2 T X MXene nano‐floating‐gates (NFG) is presented. By using solution‐phase size‐sorting followed by controlled surface oxidation process, a regulated distribution of MXene nanoflakes comprising metallic Ti 3 C 2 T X as the core surrounded by TiO 2 ‐a high dielectric constant insulator‐as the shell is achieved. The size‐sorted core/shell‐like MXene nanoflakes show a self‐sustainable charge trapping/detrapping behavior, which is highly feasible for realizing non‐embed NFGs for transistor memory devices. Interestingly, unlike the conventional NFG‐embedded architecture, the introduction of core/shell‐like MXene under an electrolyte‐gated graphene field‐effect transistor (GFET) architecture induces a cooperative evolution of the hysteresis loop associated with ionic motion in the electrolyte gates and charge trapping/detrapping in the nanoflakes, resulting in a deterministic remote doping of the graphene layer. The resulting device exhibited a highly retentive memory behavior, which can be optimized by the nanoflake size distribution. In addition, synaptic functions having mechanical flexibility can be successfully emulated using MXene‐based GFETs fabricated on a flexible polyethylene naphthalate substrate.