Highly Sensitive and Selective Gas Detection Based on Silicene

Abstract

Recent advances in the fabrication of silicene devices have raised exciting prospects for practical applications such as gas sensing. We investigated the gas detection performance of silicene nanosensors for four different gases (NO, NO 2 , NH 3 , and CO) in terms of sensitivity and selectivity, employing density functional theory and nonequilibrium Green's function method. The structural configurations, adsorption sites, binding energies and charge transfer of all studied gas molecules on silicene nanosensors are systematically discussed in this work. Our results indicate that pristine silicene exhibits strong sensitivity for NO and NO 2 , while it appears incapable of sensing CO and NH 3 . In an attempt to overcome sensitivity limitations due to weak van der Waals interaction of those latter gas molecules on the device, we doped pristine silicene with either B or N atoms, leading to enhanced binding energy as well as charge transfer, and subsequently a significant improvement of sensitivity. A distinction between the four studied gases based on the silicene devices appears possible, and thus these promise to be next-generation nanosensors for highly sensitive and selective gas detection.

A theoretical study of gas adsorption on silicene nanoribbons and its application in a highly sensitive molecule sensor

“…Finally, the moderate adsorption energies of NH 3 and CO gas molecules make SiNR a promising material for sensitive gas sensors or gas filters because they can be easily desorbed from SiNR by heating. The calculated adsorption energies of all studied gas molecules on SiNR are distinctly larger than those of silicene sheet and GNR, [49][50][51]67 showing higher sensitivity of SiNR toward the gas molecules. It should also be noted that environmental gas molecules (N 2 , CO 2 , O 2 , and H 2 O) can change the NH 3 and CO sensing capability SiNR's.…”

“…These results are consistent with earlier research on gas molecule adsorption on silicene sheet. [48][49][50][51] As previously mentioned, silicene is more reactive than graphene because of its tendency to adopt sp 2 + sp 3 hybridization over sp 2 hybridization. 22 The difference between chemical reactivities of silicene and graphene can be understood from Fig.…”

“…These findings are in a good agreement with previous studies on gas detection based on doped silicene. 50 The most stable configuration of adsorbed gas molecules on N-doped and B-doped ASiNR are depicted in Fig. 9.…”

“…22 This buckled structure makes it possible for the band gap of silicene to be tuned more intensively with an external electric field 38 and with binding adsorbates 39 as compare to graphene. 40 Furthermore, silicene shows a considerably higher chemical reactivity for atoms [41][42][43][44][45][46] and molecules [47][48][49][50][51] adsorption than graphene due its buckled formation with a great deal of potential applications for silicene based nanoelectronic devices, 52 Li-ion storage batteries, hydrogen storage, 45 thin film solar cell absorbers, 46 hydrogen separation membranes, 47 and molecule sensors. [49][50][51] Similar to graphene, silicene is a zero band gap semimetal.…”

Adsorption of gas molecules on a graphitic GaN sheet and its implications for molecule sensors

“…Two-dimensional (2D) nanomaterials, such as silicene [1][2][3][4] and phosphorene, [5][6][7] have become prominent in gas sensor applications in recent years.…”