An Analytical Conductance Model for Gas Detection Based on a Zigzag Carbon Nanotube Sensor.

Ali Hosseingholipourasl,Seyed Saeid Rahimian Koloor,Sharifah Hafizah Syed Ariffin,Michal Petrů,Mohammad Taghi Ahmadi,Afiq Hamzah

doi:10.3390/s20020357

Abstract

Recent advances in nanotechnology have revealed the superiority of nanocarbon species such as carbon nanotubes over other conventional materials for gas sensing applications. In this work, analytical modeling of the semiconducting zigzag carbon nanotube field-effect transistor (ZCNT-FET) based sensor for the detection of gas molecules is demonstrated. We propose new analytical models to strongly simulate and investigate the physical and electrical behavior of the ZCNT sensor in the presence of various gas molecules (CO2, H2O, and CH4). Therefore, we start with the modeling of the energy band structure by acquiring the new energy dispersion relation for the ZCNT and introducing the gas adsorption effects to the band structure model. Then, the electrical conductance of the ZCNT is modeled and formulated while the gas adsorption effect is considered in the conductance model. The band structure analysis indicates that, the semiconducting ZCNT experiences band gap variation after the adsorption of the gases. Furthermore, the bandgap variation influences the conductance of the ZCNT and the results exhibit increments of the ZCNT conductance in the presence of target gases while the minimum conductance shifted upward around the neutrality point. Besides, the I-V characteristics of the sensor are extracted from the conductance model and its variations after adsorption of different gas molecules are monitored and investigated. To verify the accuracy of the proposed models, the conductance model is compared with previous experimental and modeling data and a good consensus is observed. It can be concluded that the proposed analytical models can successfully be applied to predict sensor behavior against different gas molecules.

Highlights

The importance of environmental monitoring and protecting the human body from hazardous and toxic gases is a major motivation of the researchers to study and develop state of the art sensors with high sensitivity and ideal performance [1,2,3]
Lasso and genetic algorithms or Wolkenstein adsorption theory and model modeling gas sensors based on carbon nanostructures
In the modeling of ZCNT energy band structure, the interaction of the carbon atoms was taken into account by hopping integral parameter

Summary

Introduction

The importance of environmental monitoring and protecting the human body from hazardous and toxic gases is a major motivation of the researchers to study and develop state of the art sensors with high sensitivity and ideal performance [1,2,3]. Lasso and genetic algorithms or Wolkenstein adsorption theory and model modeling gas sensors based on carbon nanostructures [39,40]. These works did not for modeling gas sensors based on carbon nanostructures [39,40]. These works did not investigate devicephysics physicsand and sensing mechanism the phenomena that inside occur the inside the investigate device thethe sensing mechanism and and the phenomena that occur device, device, just to interpret the and output and formulate thecurves outputusing curves using algorithms.

Materials and Methods

Energy Band Structure Modeling

Conductance Model By Considering Gas Adsorption Effect

Conclusions