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XRD analysis for determining the cause of diminished operating power. a) X‐ray diffraction results on HfO2‐based MH. A schematic of the HfO2 grain size variation b) before and c) after annealing.
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Designing a transparent carbon nanotube (CNT) gas sensor for nitrogen dioxide (NO2) detection at room temperature (RT), which is unaffected by humidity, is a critical challenge in various technologies. To solve this issue, a filament‐based memristor heater (MH) embedded low‐power CNT gas sensor is proposed to address humidity‐related issues, and dy...
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Citations
... Memristors offer a range of advantages regarding gas-sensing applications, combining sensitivity, efficiency, and versatility. Memristors retain their state without constant energy input, unlike conventional sensors, which often require a continuous supply of power in order to maintain their operation [12,13]. Memristor-based gas sensors exhibit exceptional sensitivity by detecting traces of gas concentrations with precision, and their nanoscale dimensions enable miniaturization and integration into advanced devices. ...
... Memristor-based gas sensors exhibit exceptional sensitivity by detecting traces of gas concentrations with precision, and their nanoscale dimensions enable miniaturization and integration into advanced devices. Memristor-based gas sensors also provide rapid response and recovery, which ensure real-time monitoring in dynamic environments [13]. Their compatibility with diverse materials allows for the tailored sensing of specific gases, whereas their robustness ensures reliable performance under extreme conditions. ...
NO2 is a toxic gas that can damage the lungs with prolonged exposure and contribute to health conditions, such as asthma in children. Detecting NO2 is therefore crucial for maintaining a healthy environment. Carbon nanotubes (CNTs) are promising materials for NO2 gas sensors due to their excellent electronic properties and high adsorption energy for NO2 molecules. However, conventional CNT-based sensors face challenges, including low responses at room temperature (RT) and slow recovery times. This study introduces a memristor-based NO2 gas sensor comprising CNT/ZnO/ITO decorated with an N-[3-(trimethoxysilyl)propyl] ethylene diamine (en-APTAS) membrane to enhance room-temperature-sensing performance. The amine groups in the en-APTAS membrane increase adsorption sites and boost charge transfer interactions between NO2 and the CNT surface. This modification improves the sensor’s response by 60% at 20 ppm compared to the undecorated counterpart. However, the high adsorption energy of NO2 slows the recovery process. To overcome this, a pulse-recovery method was implemented, applying a −2.5 V pulse with a 1 ms width, enabling the sensor to return to its baseline within 1 ms. These findings highlight the effectiveness of en-APTAS decoration and pulse-recovery techniques in improving the sensitivity, response, and recovery of CNT-based gas sensors.
... This gives the gasistor a gastriggered switch and memory function [66]. The experimental results show that the addition of CFs can effectively solve the limitations of the CNT gas sensor in terms of sensitivity, recovery process, and humidity effect [58]. For instance, Chae et al. proposed a filament-based memristor heater (MH)-embedded transparent CNT gas sensor for the detection of NO2 gas at room temperature [58]. ...
... The experimental results show that the addition of CFs can effectively solve the limitations of the CNT gas sensor in terms of sensitivity, recovery process, and humidity effect [58]. For instance, Chae et al. proposed a filament-based memristor heater (MH)-embedded transparent CNT gas sensor for the detection of NO2 gas at room temperature [58]. Nanoscale conductive filaments (CFs) are used to fabricate an MH based on the insulating material hafnium oxide (HfO2) [58]. ...
... For instance, Chae et al. proposed a filament-based memristor heater (MH)-embedded transparent CNT gas sensor for the detection of NO2 gas at room temperature [58]. Nanoscale conductive filaments (CFs) are used to fabricate an MH based on the insulating material hafnium oxide (HfO2) [58]. The MH uses nanoscale CFs to apply heat directly below the sensing layer, allowing for lower power consumption and higher efficiency compared to conventional gas sensors [58]. ...
The MEMS gas sensor is one of the most promising gas sensors nowadays due to its advantage of small size, low power consumption, and easy integration. It has been widely applied in energy components, portable devices, smart living, etc. The performance of the gas sensor is largely determined by the sensing materials, as well as the fabrication methods. In this review, recent research progress on H2, CO, NO2, H2S, and NH3 MEMS sensors is surveyed, and sensing materials such as metal oxide semiconductors, organic materials, and carbon materials, modification methods like construction of heterostructures, doping, and surface modification of noble metals, and fabrication methods including chemical vapor deposition (CVD), sputtering deposition (SD), etc., are summarized. The effect of materials and technology on the performance of the MEMS gas sensors are compared.
... The HfO2 layer in our structure provides superior insulating properties and high thermal stability, effectively suppressing oxygen vacancy migration and stabilizing the CF [19]. This stabilization further enhances the gas-sensing performance by leveraging Joule heating effects, which strengthen the interaction between NO2 molecules and the SnO2 sensing layer, distinguishing our research from existing SnO2-based sensor studies [20]. In this structure, the HfO2 layer acts as an insulating material, stabilizing the CF and enhancing the overall gas-sensing performance for NO2 detection. ...
... This phenomenon can be explained by the optimized thickness of the HfO2 layer. In the HRS, the breaking of the CF generates localized heat through the Joule heating effect, which is efficiently transferred to the SnO2 sensing layer, enhancing the interaction with NO2 molecules [20,26]. The highest gas response observed at a thickness of 30 nm indicates that this thickness provides the best balance between heat generation and insulation properties. ...
We present a SnO2 gas sensor with an HfO2 layer that exhibits enhanced performance and reliability for gasistor applications, combining a gas sensor and a memristor. The transparent SnO2 gasistor with a 30 nm HfO2 layer demonstrated low forming voltages (7.1 V) and a high response rate of 81.28% to 50 ppm of NO2 gas, representing an approximately 174.86% increase compared to the response of 29.58% from the SnO2 gas sensor without the HfO2 layer. The device also showed improved power efficiency and exceptional long-term stability, with reproducibility tests over 10 days at 10 ppm NO2 showing a minimal variation of 2.4%. These results indicate that the proposed transparent memristor with the 30 nm HfO2 layer significantly enhances the device’s reliability and effectiveness for gasistor applications.
