Analytical Prediction of Highly Sensitive CNT-FET-Based Sensor Performance for Detection of Gas Molecules

Ali Hosseingholipourasl,Sharifah Hafizah Syed Ariffin,Michal Petru,Seyed Saeid Rahimian Koloor,Afiq Hamzah

doi:10.1109/access.2020.2965806

Abstract

In this study, a set of new analytical models to predict and investigate the impacts of gas adsorption on the electronic band structure and electrical transport properties of the single-wall carbon nanotube field-effect transistor (SWCNT-FET) based gas sensor are proposed. The sensing mechanism is based on introducing new hopping energy and on-site energy parameters for gas-carbon interactions representing the charge transfer between gas molecules (CO2, NH3, and H2O) and the hopping energies between carbon atoms of the CNT and gas molecule. The modeling starts from the atomic level to the device level using the tight-binding technique to formulate molecular adsorption effects on the energy band structure, density of states, carrier velocity, and I-V characteristics. Therefore, the variation of the energy bandgap, density of states and current-voltage properties of the CNT sensor in the presence of the gas molecules is discovered and discussed. The simulated results show that the proposed analytical models can be used with an electrical CNT gas sensor to predict the behavior of sensing mechanisms in gas sensors.

Highlights

The importance of monitoring of the gases using sensors and determining their concentrations and compositions is increasing because of the safety reasons and strict environmental regulations [1]–[5]
A field-effect transistor-based gas sensor based on a single-wall zigzag carbon nanotubes (CNTs) platform was modeled and applied for gas (CO2, NH3, and H2O) detection
The electronic band structure, density of states, carrier velocity and I-V characteristics of the zigzag carbon nanotube field-effect transistor (CNTFET) based gas sensor were analytically modeled by considering the molecular adsorption effects (t and E0)

Summary

INTRODUCTION

The importance of monitoring of the gases using sensors and determining their concentrations and compositions is increasing because of the safety reasons and strict environmental regulations [1]–[5]. The structural and electrical characteristics of CNTs are affected by the diameter and helicity of the formation of graphitic rings in CNT walls that lead to semiconducting or metallic nanotubes These properties are determined by the geometrical parameter called a chiral vector. Effects on the energy band gap, DOS, carrier velocity and I-V characteristics of the sensor These parameters are important factors that can be used to monitor and detect various gases and investigate the sensing mechanism in CNT based gas sensors to design highly sensitive sensors and improve sensor performance

TIGHT BINDING FORMALISM

CONCLUSION