Pristine and modified silicene based volatile organic compound toxic gas sensor: a first principles study

Abstract

In this work, we have investigated the sensitivity of two Volatile Organic Compounds (VOCs), formaldehyde (FD) and acetaldehyde (AD) on the surface of two-dimensional (2D) Armchair Silicene Nanoribbon (ASiNR) by analysing the structural, electronic and transport properties using density functional theory (DFT) and non-equilibrium Green's function (NEGF) formalism. Different models of ASiNR have been considered viz; pristine, Al-doped, P-doped, Al/P co-doped and vacancy-defected ASiNR. The findings revealed that the vacancy-defected models shows a significant increase in the adsorption energies for both VOCs compared to other models. Apart from that, in all the models, the current increases with the applied voltage and the maximum value of current was found in Al/P co-doped model at a higher bias voltage of 2 V. The variation of the computed transmission spectrum peaks from -2 to 2 eV of energy values also confirms the sensitivity of the proposed models towards the VOC molecules. Moreover, the projected device density of states (PDDOS) revealed that all the models remain semiconducting before and after adsorption, which completely agrees with the transmission spectrum. Furthermore, Al/P co-doped model shows high sensitivity of 68% and77% towards FD and AD molecules respectively. Thus, it is concluded that the modeled ASiNR VOC gas sensors will aid in sensing cancer.

Theoretical Study of Electronic and Thermoelectric Properties of Ultra-Thin Silicene and Germanene

“…In theoretical research, silicene and other nanostructures can be studied by employing the popular classical molecular dynamics simulation [16]. Unfortunately, we did not find interatomic potential to accurately characterize the unique properties of silicene, for example, the low-bending structure and corresponding torsional distance that emerge through reproducing experiments [17] and preliminary calculations [18]. From early studies, Ge was thought to form a single-layer hexagonal lattice called germanene [19].…”

Tailoring gas sensing properties of WS2 monolayer via Nb and Co embedding for highly sensitive and selective detection of HCN and H2S gases: a first principle study

“…Qin et al have evaluated the effect of the number of layers on the recovery rate of the WS 2 for ammonia detection and found that the recovery time linearly decreased with the decrease of the number of layers with the fast recoverable time for the WS 2 monolayer at room temperature [18]. On the other hand, several theoretical studies demonstrated that surface modification can significantly amplify the mutual interaction between the monolayer and gas molecules, thereby elevating the chemical interactions between the host layer and target molecules leading to a heightened sensitivity of the monolayer [19][20][21][22]. In recent research, it has been found that the introduction of Ni into WS 2 can significantly enhance the adsorption energy of H 2 , CO, and C 2 H 2 , leading to significant chemical reactions accompanied by a decrease in the band gap, specifically associated with the adsorption of C 2 H 2 .…”