Analytical Modeling of Nh3 Gas Sensing Using Zigzag Graphene Nanoscrolls: Energy Band Structure and Electrical Properties

Abstract

Graphene nanoscrolls (GNSs), a unique nanostructure of graphene, have garnered considerable attention due to their distinctive properties such as a rolled-up papyrus-like structure, adjustable core geometry, increased inner wall area, and enhanced surface-to-volume ratio. These properties make GNS a promising candidate for various nanoelectronic applications, including gas sensing devices. Despite its potential, GNS has been relatively underexplored in the context of gas sensing applications. In this study, we present a series of analytical models to characterize the behavior of zigzag graphene nanoscrolls (ZGNS)-based gas sensors in the presence of NH3 gas. The tight-binding technique, employing nearest neighbor approximation, is utilized to formulate the energy dispersion relation of GNS, incorporating the influence of gas molecule adsorption through parameters such as the hopping integral between GNS and gas and the on-site energy of adsorbed gas molecules. Furthermore, the derived energy equation is employed to establish the conductance relation and explore the impact of gas adsorption on the electrical conductance of GNS. Subsequently, the I-V characteristics of the GNS sensor are formulated, and the variations in current due to NH3 gas exposure are analyzed. The gate voltage is modeled as a function of NH3 concentration, and a sensing parameter is proposed based on current variations across different concentrations. Validation of the model is performed by comparing the obtained results with data extracted from previous studies. The findings demonstrate good agreement, underscoring the effectiveness of the proposed ZGNS-based sensor model for NH3 detection under varying environmental conditions.