Antimony oxide nanostructures in the monolayer limit: self-assembly of van der Waals-bonded molecular building blocks
| Autor: | Maxime Le Ster, Tai-Chang Chiang, Sara Salehitaleghani, Simon Brown, Peng Wang, Xiaoxiong Wang, Pawel J. Kowalczyk, Guang Bian, Tobias Märkl, Matthew Snyder |
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| Rok vydání: | 2020 |
| Předmět: |
Nanostructure
Materials science chemistry.chemical_element Bioengineering 02 engineering and technology 010402 general chemistry 01 natural sciences law.invention symbols.namesake Lattice constant Antimony Highly oriented pyrolytic graphite law Monolayer General Materials Science Electrical and Electronic Engineering Mechanical Engineering General Chemistry 021001 nanoscience & nanotechnology 0104 chemical sciences chemistry Mechanics of Materials Chemical physics symbols Scanning tunneling microscope Antimony oxide van der Waals force 0210 nano-technology |
| Zdroj: | Nanotechnology. 32(12) |
| ISSN: | 1361-6528 |
| Popis: | Antimony oxide nanostructures have been identified as candidates for a range of electronic and optoelectronic applications. Here we demonstrate the growth of 2-dimensional antimony oxide nanostructures on various substrates, including highly oriented pyrolytic graphite (HOPG), MoS2 and α-Bi(110) nanoislands. Using scanning tunneling microscopy (STM) we show that the nanostructures formed are exclusively highly crystalline α-Sb2O3(111) monolayers with a lattice constant of 796 pm ± 7 pm. The nanostructures are triangular with lateral dimensions of up to ∼30 nm. Even though elemental antimony nanostructures are grown simultaneously mixed phases are not observed and both materials exhibit their own distinct growth modes. Moiré patterns are also observed and simulated, allowing confirmation of the atomic unit cell and an understanding of the orientation of the Sb2O3 structures with respect to the supporting materials. As in the bulk, the Sb2O3 nanostructures are formed from Sb4O6 molecules that are weakly interacting through van der Waals forces. This allows physical modification of the nanostructures with the STM tip. Scanning tunnelling spectroscopy reveals a wide band gap of at least 3.5 eV. Finally, we show that possible alternative structures that have unit cells comparable to those observed can be excluded based on our DFT calculations. The considered structures are a 2 × 2 reconstruction of β-Sb with one vacancy per unit cell and a van der Waals solid composed of Sb4 clusters. Previous reports have predominantly demonstrated Sb2O3 structures with much larger thicknesses. |
| Databáze: | OpenAIRE |
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