Adsorption and optical properties of H 2 S, CH 4 , NO, and SO 2 gas molecules on arsenene: a DFT study
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Adsorption and optical properties of H2S, CH4, NO, and SO2 gas molecules on arsenene: a DFT study Arshiya Abooali1 · Fatemeh Safari1 Received: 4 March 2020 / Accepted: 30 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract The adsorption and optical properties of H 2S, CH4, NO, and S O2 gas molecules onto arsenene is investigated by density functional theory. The NO gas molecule significantly modifies the band structure and density of states near the Fermi level, which suggests that arsenene is more sensitive to this gas molecule. The results indicate that arsenene exhibits weak sensitiv H4 molecules. The current–voltage (I–V) characteristics before and after gas exposure are calculated using ity to H 2S and C the nonequilibrium Green’s function formalism. The I–V characteristics of the sensor demonstrate high sensitivity to NO gas molecules. Moreover, the current passing through arsenene is remarkably improved after SO2 adsorption under a bias voltage of 2.8 V. In addition, exposure to NO and SO2 gas molecules modifies the optical spectrum of arsenene. Therefore, arsenene could be a promising candidate for NO and SO2 optical gas sensors. Keywords Arsenene · Gas adsorption · DFT · NEGF · Dielectric function
1 Introduction Rapid industrial development has led to increasing environmental pollution from factory waste and other industrial by-products, which must be monitored with the use of sensors in various conditions and locations [1, 2]. A critical factor in monitoring environmental pollution is the sensing of toxic gas molecules [3]. Automobile exhaust and burning of coal and oil are the main sources of NO gas molecule production [4]. At room temperature, the NO gas molecule is nonflammable, colorless, and extremely toxic by inhalation. The H2S gas molecule, which can have harmful and irreparable effects on the nervous system, is characterized as a colorless, corrosive, and flammable toxic gas [5]. SO2, a toxic gas molecule and a leading source of acid rain, is produced in the pharmaceutical and chemical industries. S O2 can cause serious harm to the human body and environment at levels exceeding a specific concentration [6]. Although the CH4 gas molecule is nontoxic, it can be flammable. As mentioned above, the noxious impacts of NO, H 2S, and S O2, and also the explosion danger of CH4, make them significant * Fatemeh Safari [email protected] 1
Department of Electrical Engineering, Dezful Branch, Islamic Azad University, Dezful, Iran
and volatile in low concentrations. Two-dimensional (2D) materials have been recently used in order to detect a low concentration of these gas molecules in industry with a practical and proper technique [5]. Since the successful experimental production of graphene in 2004, intensive research efforts have been focused on 2D materials [7–12]. These materials have great potential for gas sensing due to their unique properties and large surfaceto-volume ratio [3]. Graphene and MoS2 have been studied as gas-sensing mat
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