Ferroelectric synaptic transistors have gained significant attention for neuromorphic applications owing to their low power consumption and high‐speed modulation. However, charge trapping in ferroelectric films introduces nonlinearity, instability, and poor reproducibility during synaptic weight updates. A buried gate‐structured InGaZnO synaptic transistor with an Al ₂ O ₃ /HfO ₂ dielectric stack is demonstrated in this study to achieve unprecedented conductance modulation by leveraging the frequency‐dependent coupling between ferroelectric polarization and charge trapping. The versatile conductance‐tuning capability of double switching modes enables even single‐polarity voltage‐driven potentiation and depression while simultaneously achieving highly linear conductance modulation. The diffusion of Al atoms into the HfO ₂ layer promotes additional oxygen vacancies, which contribute to the emergence of deep‐level trap states. These defects also facilitate noncentrosymmetric crystal‐phase stabilization through spontaneous symmetry breaking, thereby inducing ferroelectricity, which is corroborated by density‐functional‐theory simulations and piezoelectric‐force‐microscopy measurements. By fully utilizing dual‐mode operation, the device achieves highly linear conductance updates with a minimum nonlinearity of 0.47 and enables potentiation and depression under a pulse‐train configuration with a single voltage polarity. The system attains a high pattern‐recognition accuracy of 97.03% for handwritten digit classification. This dual‐mode operation strategy provides a compelling pathway for simplifying the architecture of integrated neuromorphic circuits and enhancing their computational efficiency.

The low-dimensional metal halide Cs₃Cu₂I₅ exhibits unique electrical and chemical properties. Notably, it undergoes a phase transition to CsCu₂I₃ upon exposure to hydroxyl (-OH) gas, resulting in significant changes in its electrical characteristics. In this study, we developed a highly selective semiconductor-based gas sensor utilizing Cs₃Cu₂I₅. The material was synthesized on an Al₂O₃ substrate with carbon electrodes using a solution-based process, enabling gas sensing based on its electrical properties. The sensor was further integrated into an Arduino-based real-time monitoring system for wearable applications. The final system was mounted onto a face mask, enabling the real-time detection of human respiration. This research presents a next-generation sensor platform for real-time respiratory monitoring, demonstrating the potential of Cs₃Cu₂I₅ in advanced wearable bio-gas sensing applications.