Direct deposition of (Bi$_x$Sb$_{1– x}$)$_2$Te$_3$ nanosheets on Si/SiO$_2$ substrates by chemical vapor transport
Dépôt en phase vapeur de Nanostructures (Bi$_x$Sb$_{1– x}$)$_2$Te$_3$ sur des substrats Si/SiO$_2$
Résumé
The tellurides of Bismuth and Antimony (Bi2Te3 and Sb2Te3) are prominent members of the V2VI3 material family that exhibit promising topological properties. We provide a method for the rational synthesis of mixed crystals of these mate-rials ((BixSb1−x)2Te3 with x = 0.1, …, 0.9) by means of a bottom-up CVT approach. Thermodynamic calculations showed the synthesis to be possible in the temperature range of 390 – 560°C without significant enrichment of either component and without adding a transport agent. The starting materials were synthesized and verified by XRD. Optimization exper-iments showed the ideal conditions for nanosheet synthesis to be T2 = 560°C, T1 = 390°C with a reaction time of t = 36 h. Crystals with heights of down to 12 nm (12 quintuple layers) were synthesized and analyzed by means of scanning elec-tron microscopy, energy-dispersive X-ray spectrometry and atomic force microscopy. High resolution transmission elec-tron microscopy confirmed the R3̄m crystal structure, high crystallinity and overall quality of the synthesized (BixSb1−x)2Te3 nanosheets. Magneto-transport measurements revealed that such ternary compounds can have a signifi-cantly reduced carrier density compared to the binary parent compounds.
Domaines
MatériauxOrigine | Fichiers produits par l'(les) auteur(s) |
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Domaine public
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