隨著全球對環境永續發展與穿戴式電子技術的日益重視，半導體科技正積極朝向具備生物降解性與相容性之綠色電子元件領域深入發展。在眾多生物材料中，天然來源的高分子材料明膠，因具備極佳的機械柔韌性、卓越的光學穿透率，以及與低溫溶液製程高相容性，被視為構築永續型記憶體元件的理想候選者。儘管如此，目前多數文獻發表的以生物材料為基底的記憶體，仍面臨高度不穩定性與重現性不佳等挑戰，限制了其在神經形態運算中的實際應用價值。
有鑑於此，本研究藉由在明膠基質中摻雜適量硝酸鉀金屬鹽類，並搭配簡易的低溫溶液製程，成功開發出一種免形成、高柔韌性的雙極性切換電阻式記憶體元件。本研究的核心價值在於鉀離子的引入，有效促進了薄膜內部的離子遷移，進而克服了傳統生物高分子元件中導電燈絲隨機分佈的缺點。
從電性結果來看，透過適量鉀離子的添加，操作電壓成功由未摻雜前的 – 0.8 V 降低至 – 0.5 V，證實元件得以在更低的電壓下引導燈絲形成，開關比則由未摻雜前的 102 大幅提升至 104 以上，且數據保持時間高達 104 秒以上；此外，在穩定性測試方面，無論是經歷連續 100 次的循環操作，亦或是放置於大氣環境下長達 200 天，元件依舊能維持 103 以上的優異開關比，展現出極佳的耐受力與長期壽命。同時，元件在高阻態下的電流變異係數由原本的 38% 顯著降低至 17% 以下，以上比較結果展現出摻雜適量鉀離子之元件的高穩定性與循環重現性，此一優異的電學表現，亦透過物理特性分析獲得了進一步證實，明確揭示了限域效應能有效鎖定導電燈絲的生長範圍。基於此電性特質與離子遷移特性，該元件進一步成功模擬了多項生物突觸可塑性行為，包括長時程增強（long-term potentiation）、長時程抑制（long-term depression）、成對脈衝促進（paired-pulse facilitation）、成對脈衝抑制（paired-pulse depression）特性。
總結而言，本研究證實明膠基複合薄膜之生物電子可望應用於次世代永續記憶體，成功開拓了一條兼具環境保護、低成本製造與高效能神經形態運算之嶄新路徑。

Driven by the growing global emphasis on environmental sustainability and wearable electronics, semiconductor technology is actively advancing into the field of green electronic devices featuring biodegradability and biocompatibility. Among various biomaterials, gelatin, a naturally derived polymer, is considered an ideal candidate for constructing sustainable memory devices due to its excellent mechanical flexibility, outstanding optical transmittance, and high compatibility with low-temperature solution processes. Nevertheless, most currently reported biomaterial-based memories still suffer from severe instability and poor reproducibility, which restricts their practical application value in neuromorphic computing architectures.
To address these challenges, this study successfully developed a forming-free, highly flexible bipolar switching resistive random access memory by doping an appropriate amount of potassium nitrate (KNO3) metal salt into a gelatin matrix, combined with a simple low-temperature solution process. The core value of this work lies in the introduction of potassium ions, which effectively accelerates internal ion migration within the thin film, thereby overcoming the drawback of random conducting filament distribution inherent in conventional biopolymer-based devices.
Electrical characterization reveals that incorporating an optimal amount of potassium ions successfully reduces the operating voltage from – 0.8 V to – 0.5 V, demonstrating that the device can reliably induce filament formation under lower voltage conditions. Concurrently, the ON/OFF ratio is significantly enhanced from 102 to over 104, accompanied by a data retention time exceeding 104 seconds. Furthermore, in terms of reliability testing, the device maintains an outstanding ON/OFF ratio of over 103 even after undergoing 100 continuous switching cycles or being exposed to the ambient atmosphere for up to 200 days, demonstrating exceptional environmental tolerance and long-term lifespan. Crucially, the coefficient of variation for the current in the high-resistance state (HRS) drops dramatically from 38% to below 17%. These comparative outcomes clearly manifest the exceptional stability and cyclic reproducibility of the device optimized with an appropriate dosage of potassium ions. Such outstanding electrical behavior is further substantiated by physical characterization, which explicitly reveals that the confinement effect effectively locks the spatial growth zone of the conducting filaments. Benefiting from these superior electrical traits and dynamic ion migration characteristics, the device further successfully emulates various essential biological synaptic plasticity behaviors, including long-term potentiation（LTP）, long-term depression（LTD）, paired-pulse facilitation（PPF）, and paired-pulse depression（PPD）.
In summary, this study confirms that gelatin-based composite film bioelectronics hold great promise for next-generation sustainable memory applications, successfully pioneering a novel pathway that integrates environmental protection, low-cost fabrication, and high-performance neuromorphic computing.

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