Bridging Mode-Specific Performance Gaps in Organic Charge-Modulated Transistor Platforms via Coupled Interfacial Boundary Engineering

In this study, the thickness and density of AlOx dielectrics were precisely controlled by tuning the anodizing voltage, and the correlation between the dielectric electrical properties and OCMFET device performance was systematically investigated. Increasing the anodizing voltage resulted in a linear increase in AlOx dielectric thickness, accompanied by a reduction in leakage current and an enhancement in breakdown voltage, thereby directly modulating the charge coupling efficiency through changes in the effective control gate–floating gate capacitance. High capacitance can be achieved under low anodizing voltage conditions. However, limited dielectric insulation stability leads to increased gate leakage and degraded device reliability. In contrast, high anodizing voltages increase the dielectric thickness, resulting in reduced capacitance and a limited amount of charge induced from the control gate to the floating gate. This, in turn, suppresses the threshold voltage shift and transconductance. These results confirm the existence of an optimal anodizing voltage range in which sufficient insulation characteristics and efficient charge induction are simultaneously achieved. Furthermore, interfacial charge stability was improved by introducing a TDPA-based self-assembled monolayer (SAM) on the floating gate surface. OCMFETs with simultaneously optimized dielectric and surface properties effectively amplified floating gate potential modulation under control gate operation, leading to highly sensitive changes in channel current. These results suggest that OCMFETs can be extended to multifunctional sensor platforms capable of detecting various external stimuli, including pressure, chemical, and biological signals, with high sensitivity.