Electrode Placement Effect And Tube Length Effect Of Anodized Aluminum Oxide Template Based Gas Sensor

Gas sensors have been widely used in the industrial production,environmental monitoring,health care,etc.To achieve high performance,fast response and long-time stability,various kinds of material has been investigated,such as semiconductor metal oxide?SMO?,polymer,carbon nanotube,graphene,etc.Up to now,SMO has played a domain role in the market of gas sensor field due to its stable characteristic.Among them,widely used material is ZnO,SnO₂,In₂O₃ and so on.Although these kinds of material have been used for decades,lots of researchers are still devoted to improve the sensitivity,selectivity,response rate and operating temperature.Many strategies have been applied to improve the performance of gas sensor,such as dope other materials in the gas sensing material to improve the adsorption performance of determined gas.Besides,another popular way to achieve higher sensitivity is to increase the effective gas and material reaction surface.Nanomaterials have been widely used in the field of gas sensor because of their small size effect and surface effect,which can effectively increase the surface-to-volume ratio of the material.Many nanostructures have been used in the structure of gas sensor,such as nanowire,nanotube and porous nanostructure.Porous structure of SMO is also intensively studied due to its large surface area and good gas diffusion effect.In many kinds of porous structures,anodic alumina template?AAO?structure has been used to fabricate porous structure gas sensor because of its large surface-to-volume ratio,more effective tube and the easily controllable AAO tube diameter and the pitch of the tube.Reports have shown that the reaction rate is closely related to the structure of AAO tube,such as tube diameter and the tube size distribution.In this paper,we constructed AAO template based ZnO gas sensor and simulated the reaction between the gas sensor and NO₂ with the Silvaco TCAD to study the electrode placement and tube length effect of AAO template based ZnO gas sensor.In the study of electrode placement effect,we found that different electrodes placement lead to the difference of the sensitivity by the I-V curves and analysis.We use the electric field distribution to explain the electrode placement effect of AAO structure ZnO gas sensor.During the study of the AAO tube length effect of AAO template based ZnO gas sensor,we have made the simulations with the tube length increasing to explore the tube length effect.With longer AAO tube,the effective reaction surface area is widely believed to further increase leading to a higher sensitivity.However,we analyze the tube length effect through 3D current density distribution figures generated from the simulation software.Through the study of electrode placement effect and tube length effect of AAO template based ZnO gas sensor,we can improve the sensitivity of the AAO template based gas sensor by change the electrodes placement to the best position and increase the AAO tube length.