The cluster-assembled nanowires based on M₁₂N₁₂ (M = Al and Ga) clusters as potential gas sensors for CO, NO, and NO₂ detection

Abstract

The advances in cluster-assembled materials where clusters serve as building blocks have opened new opportunities to develop ever more sensitive gas sensors. Here, using density functional theory calculations, the structural and electronic properties of cluster-assembled nanowires based on M12N12 (M = Al and Ga) clusters and their application as gas sensors have been investigated. Our results show that the nanowires can be produced via the coalescence of stable M12N12 fullerene-like clusters. The M12N12-based nanowires have semiconducting electrical properties with direct energy gaps, and are particularly stable at room temperature for long enough to allow for their characterization and applications. Furthermore, we found that the CO, NO, and NO2 molecules are chemisorbed on the M12N12-based nanowires with reasonable adsorption energies and apparent charge transfer. The electronic properties of the M12N12-based nanowires present dramatic changes after the adsorption of the CO, NO, and NO2 molecules, especially their electric conductivity. However, the adsorption of NO2 on the Al12N12-based nanowire is too strong, indicating an impractical recovery time as NO2 sensors. In addition to this, due to reasonable adsorption energies, apparent charge transfer, change in the electric conductivity, and the short recovery time, the Al12N12-based nanowire should be a good CO and NO sensor with quick response as well as short recovery time, while the Ga12N12-based nanowire should be a promising gas sensor for CO, NO, and NO2 detection.

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

“…34 The accuracy of the GGA-PBE and DNP combination to be used in investigations of the structural and electronic properties of (gases adsorption on) GaN systems has been demonstrated. 16,17,[35][36][37] 3. Results and discussion…”

“…Particularly, the adsorption of O 2 molecule on the PL-GaN sheet is endothermic, indicating that the PL-GaN sheet is very inert to oxidation, similar to that of O 2 adsorption on GaN nanowires. 17 The adsorption of H 2 molecule on the PL-GaN surface is very different from the adsorption of hydrogen at the GaN surface. 48,49 Krukowski group 48,49 has found that for relatively low hydrogen coverage, the H 2 molecule adsorbs dissociatively, leading to disintegrating into separate H atoms at GaN (0001) surface.…”

“…The adsorption of NO (or NO 2 ) molecule introduces spin polarization in the PL-GaN sheet, which has a magnetic moment of about 1 m B , indicating that magnetic properties of the PL-GaN sheet is changed obviously due to the adsorption of NO (or NO 2 ) molecule, which is similar to the cases of NO (or NO 2 ) on Ga 12 N 12 nanocluster 16 and nanowires. 17 However, the net spin polarization of the PL-GaN sheet is not modied due to the adsorption of other molecules. In this regard of the change of magnetic properties, the PL-GaN sheet is highly selective.…”

“…[11][12][13][14][15][16][17][18] For example, in two recent studies, we have demonstrated theoretically that Ga 12 N 12 nanoclusters are potentially good NO, NO 2 , and HCN gas sensors, 16 and clusterassembled nanowires based on the Ga 12 N 12 cluster can be an appropriate gas sensor for CO, NO, and NO 2 detection. 17 However, as we know, the investigation of 2D GaN as gas sensors has not been reported. In recent years, a large number of 2D semiconductor materials in the group III-V family are identied since 2D materials present a whole new class of materials whose properties differ from those of their threedimensional (3D) counterparts and hold great promise in nanodevice applications.…”

Thermodynamic photoinduced disorder in AlGaN nanowires

“…[30][31][32] Even though GaN nanowire-based devices, including tunnel-injected DUV light-emitting diodes (LEDs) 33 and LEDs for monolithic metal-optoelectronics 34 and high-power light emitters, 35 have recently been realized, understanding and optimizing the electrothermal characteristics 36,37 of GaN-based nanowires is critical for identifying and achieving their full potential in opto-electrothermal device applications. 38,39 As a consequence of the thermal activation of non-radiative recombination channels, we observed an increasing trend in the amount of generated photoinduced entropy of the InGaN nanowire system as its temperature approached room temperature, which is a valid assessment of the thermodynamic disorder in photoluminescent semiconducting materials. 40 Furthermore, the non-radiative photocarrier recombination lifetimes in nanostructured materials are naturally shorter than those of bulk structures owing to their higher surface-to-volume ratios.…”