چكيده به لاتين
Recently, gas sensors have attracted significant attention for their potential in diagnosing various diseases, including cancer. Two-dimensional (2D) materials are up-and-coming candidates for the design and development of gas sensors due to their large surface area, high carrier mobility, and layered structure. Research on 2D materials began with the synthesis of graphene in 2004. Despite its numerous advantages, its lack of an intrinsic energy gap and flat structure has limited its applicability in electronic devices. As a result, attention has shifted to other two-dimensional monolayers of group IV elements, such as silicene, germanene, and stanene. Stanene, a two-dimensional layer of tin atoms, has emerged as one of the most extensively studied 2D materials in recent years. Its buckled structure and strong intrinsic spin-orbit coupling (SOC) make it a fascinating material for various electronic applications, including field-effect transistors (FETs) and gas sensors. The SOC effect in stanene opens a band gap, and its buckled structure enhances its performance in FET devices. These unique properties make stanene a desirable candidate for the design of electronic devices, particularly gas sensors. This work explores the potential of armchair stanene nanoribbons as gas sensors using density functional theory (DFT) and the non-equilibrium Green’s function (NEGF) method. The electronic properties, such as the density of states (DOS), band structure, and adsorption energies, were analyzed through DFT calculations. Furthermore, the impact of gas adsorption on electronic transport properties was simulated using the non-equilibrium Green’s function (NEGF) method. Previous studies have identified acetonitrile, benzene, isoprene, methanol, toluene, and styrene as the most commonly detected gases in the exhaled breath of lung cancer patients. Gas adsorption can significantly change the electronic properties of sensors. In this study, we analyzed the adsorption energy, band structure, and density of states (DOS) to evaluate the adsorption characteristics and assess the sensing performance of stanene-based gas sensors. While density functional theory (DFT) is an efficient method for analyzing many electronic properties, this method is not suitable for calculating electrical transport properties. Instead, the non-equilibrium Green’s function (NEGF) method is employed for the computation of electronic transport. Changes in the electronic structure can significantly impact experimentally measurable transport properties. In addition, changes in resistance, conductivity, and charge transfer are commonly used to determine sensor performance. The findings of this study demonstrate that stanene nanoribbons exhibit high performance in detecting gas biomarkers associated with lung cancer. Furthermore, structural defects in the nanoribbons, such as vacancies, were shown to modify both the energy gap and electronic properties of stanene. This research explores the influence of such defects on the sensing properties of stanene nanoribbons, revealing that the presence of defects enhances their sensing performance. Furthermore, we investigated the influence of vertical and transverse electric fields on the adsorption properties of armchair stanene nanoribbons. Our results indicate that applying electric fields in the negative direction enhances the sensing performance, while electric fields applied in the positive direction reduce it. Throughout this study, it was assumed that the nanoribbon edges are hydrogenated to passivate the effect of dangling bonds. In addition, we examined the impact of edge halogenation on the sensing properties of stanene. Additionally, we explore the impact of edge halogenation on the sensing properties. our findings reveal that halogenation further improves sensing performance compared to hydrogenation.
