Individual hollow and mesoporous aero-graphitic microtube based devices for gas sensing applications
Individual hollow and mesoporous aero-graphitic microtube based devices for gas sensing applications
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DOI：
10.1063/1.4989841
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发表时间：
2017-06
影响因子：
4
通讯作者：
O. Lupan;V. Postica;J. Marx;M. Mecklenburg;Y. Mishra;K. Schulte;B. Fiedler;R. Adelung
中科院分区：
文献类型：
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作者：
O. Lupan;V. Postica;J. Marx;M. Mecklenburg;Y. Mishra;K. Schulte;B. Fiedler;R. Adelung
在这项工作中，单独的中空和介孔石墨微管集成到电子设备使用FIB/SEM系统，并通过施加不同的偏置电压（在10 mV-1 V的范围内）作为气体和蒸汽传感器进行了研究。通过增加偏置电压，观察到轻微的电流增强，这主要归因于自加热效应。报道了一种不同的氨NH3蒸气传感行为，通过增加所施加的偏置电压，空心和中孔微管直径下降到300 nm。在中空微管的情况下，观察到响应的增加，而中孔微管的相反效果已经被注意到。这可能是由于中孔微管比中空微管具有更高的比表面积。因此，在室温下，当表面化学反应速率（k）高于气体扩散速率（DK）时，具有较大SSA的结构具有较高的响应。通过增加偏置电压，即，结构的总温度DK成为气体响应的限制步骤。因此，在较高的偏置电压下，较大的孔将促进增强的气体扩散，即，更高的气体响应。本研究证明了材料孔隙率对气体传感应用的重要性。在这项工作中，单独的中空和介孔石墨微管集成到电子器件中使用FIB/SEM系统，并通过施加不同的偏压（在10 mV-1 V的范围内）作为气体和蒸汽传感器进行了研究。通过增加偏置电压，观察到轻微的电流增强，这主要归因于自加热效应。报道了一种不同的氨NH3蒸气传感行为，通过增加所施加的偏置电压，空心和中孔微管直径下降到300 nm。在中空微管的情况下，观察到响应的增加，而中孔微管的相反效果已经被注意到。这可能是由于中孔微管比中空微管具有更高的比表面积。因此，在室温下，当表面化学反应速率（k）高于气体扩散速率（DK）时，具有较大SSA的结构具有较高的响应。通过增加偏置电压…
In this work, individual hollow and mesoporous graphitic microtubes were integrated into electronic devices using a FIB/SEM system and were investigated as gas and vapor sensors by applying different bias voltages (in the range of 10 mV–1 V). By increasing the bias voltage, a slight current enhancement is observed, which is mainly attributed to the self-heating effect. A different behavior of ammonia NH3 vapor sensing by increasing the applied bias voltage for hollow and mesoporous microtubes with diameters down to 300 nm is reported. In the case of the hollow microtube, an increase in the response was observed, while a reverse effect has been noticed for the mesoporous microtube. It might be explained on the basis of the higher specific surface area (SSA) of the mesoporous microtube compared to the hollow one. Thus, at room temperature when the surface chemical reaction rate (k) prevails on the gas diffusion rate (DK) the structures with a larger SSA possess a higher response. By increasing the bias voltage, i.e., the overall temperature of the structure, DK becomes a limiting step in the gas response. Therefore, at higher bias voltages the larger pores will facilitate an enhanced gas diffusion, i.e., a higher gas response. The present study demonstrates the importance of the material porosity towards gas sensing applications.In this work, individual hollow and mesoporous graphitic microtubes were integrated into electronic devices using a FIB/SEM system and were investigated as gas and vapor sensors by applying different bias voltages (in the range of 10 mV–1 V). By increasing the bias voltage, a slight current enhancement is observed, which is mainly attributed to the self-heating effect. A different behavior of ammonia NH3 vapor sensing by increasing the applied bias voltage for hollow and mesoporous microtubes with diameters down to 300 nm is reported. In the case of the hollow microtube, an increase in the response was observed, while a reverse effect has been noticed for the mesoporous microtube. It might be explained on the basis of the higher specific surface area (SSA) of the mesoporous microtube compared to the hollow one. Thus, at room temperature when the surface chemical reaction rate (k) prevails on the gas diffusion rate (DK) the structures with a larger SSA possess a higher response. By increasing the bias volt...