Doping and defect-induced germanene: A superior media for sensing H 2 S, SO 2, and CO 2 gas molecules

Abstract

First-principles calculations based on density functional theory (DFT) have been employed to investigate the structural, electronic, and gas-sensing properties of pure, defected, and doped germanene nanosheets. Our calculations have revealed that while a pristine germanene nanosheet adsorbs CO2 weakly, H2S moderately, and SO2 strongly, the introduction of vacancy defects increases the sensitivity significantly which is promising for future gas-sensing applications. Mulliken population analysis imparts that an appreciable amount of charge transfer occurs between gas molecules and a germanene nanosheet which supports our results for adsorption energies of the systems. The enhancement of the interactions between gas molecules and the germanene nanosheet has been further investigated by density of states. Projected density of states provides detailed insight of the gas molecule's contribution in the gas-sensing system. Additionally, the influences of substituted dopant atoms such as B, N, and Al in the germanene nanosheet have also been considered to study the impact on its gas sensing ability. There was no significant improvement found in doped gas sensing capability of germanene over the vacancy defects, except for CO2 upon adsorption on N-doped germanene.

Promoting sensitivity and selectivity of HCHO sensor based on strained InP3 monolayer: A DFT study

“…However, it seems that the related research is limited in pristine or modified graphene. The family of 2D material is growing rapidly in recent years, including silicone [15], germanane [16], phosphorus allotropes [17,18], MXenes, and transition-metal dichalcogenides (TMDs) [19,20]. Therefore, extending the research to other 2D materials is a promising way and may help us find a more sensitive material for HCHO detecting.…”

Xenes as an Emerging 2D Monoelemental Family: Fundamental Electrochemistry and Energy Applications

“…[204] Recently, first-principles calculation found that germanene has enhanced stability due to a big dissociation energy barrier, compared with the extremely active silicene in oxygen atmosphere. [205,206] In general, hydrogenation [207] and fluorination, [208] organic functional group termination, [209,210] heteroatom doping, [211,212] and reconstructions of germanene induced by small molecules [206,213,214] could increase the environmental stability. Actually, Xanes (H-chemisorption of 2D-Xenes) as the most representative materials endow the lower energy of the ligand-Xenes-orbital antibonding levels, thus making it more stable than the precursors.…”

Recent Progress on Germanene and Functionalized Germanene: Preparation, Characterizations, Applications, and Challenges

“…In addition, functionalization of germanene has been regarded as an effective strategy to tailor its band structure and electronic properties. Recently, several theoretical simulations have been reported on chemical functionalization of germanene by hydrogenation and fluorination, organic functional group termination, foreign element doping (Ti, V, Cr, Mn, Fe, Ni, As, and Ga), and surface absorption of atoms or molecules (CO, CO 2 , H 2 O, NH 3 , and N 2 ) . There have been several theoretical reports in which it was found that the functionalized germanene could present intriguing physical and topological properties relating to the QSHE, magnetic properties, metallic ferromagnetism, and highly anisotropic optical responses .…”