Preferential Positioning, Stability, and Segregation of Dopants in Hexagonal Si Nanowires
| Autor: | Michele Amato, Stefano Ossicini, Riccardo Rurali, Enric Canadell |
|---|---|
| Přispěvatelé: | Institut du Développement et des Ressources en Informatique Scientifique (France), Agence Nationale de la Recherche (France), Ministerio de Economía, Industria y Competitividad (España), Generalitat de Catalunya, Università degli studi di Modena e Reggio Emilia |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Formation energy 2H−Si Nanowire Bioengineering 02 engineering and technology Electronic structure Nanowires hexagonal diamond silicon 2H−Si dopants density functional theory formation energy Dopants Lattice (order) General Materials Science Nanoscopic scale Hexagonal diamond silicon Condensed matter physics Dopant Nanowires Mechanical Engineering Doping General Chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 2H-Si density functional theory dopants formation energy hexagonal diamond silicon Quantum dot Density functional theory 0210 nano-technology |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname Nano letters (Online) 19 (2019): 866–876. doi:10.1021/acs.nanolett.8b04083 info:cnr-pdr/source/autori:Amato M.; Ossicini S.; Canadell E.; Rurali R./titolo:Preferential Positioning, Stability, and Segregation of Dopants in Hexagonal Si Nanowires/doi:10.1021%2Facs.nanolett.8b04083/rivista:Nano letters (Online)/anno:2019/pagina_da:866/pagina_a:876/intervallo_pagine:866–876/volume:19 |
| DOI: | 10.1021/acs.nanolett.8b04083 |
| Popis: | We studied the physics of common p- and ntype dopants in hexagonal-diamond Si, a Si polymorph that can be synthesized in nanowire geometry without the need of extreme pressure conditions, by means of first-principles electronic structure calculations and compared our results with those for the well-known case of cubic-diamond nanowires. We showed that (i) as observed in recent experiments, at larger diameters (beyond the quantum confinement regime) p-type dopants prefer the hexagonaldiamond phase with respect to the cubic one as a consequence of the stronger degree of three-fold coordination of the former, while n-type dopants are at a first approximation indifferent to the polytype of the host lattice; (ii) in ultrathin nanowires, because of the lower symmetry with respect to bulk systems and the greater freedom of structural relaxation, the order is reversed and both types of dopant slightly favor substitution at cubic lattice sites; (iii) the difference in formation energies leads, particularly in thicker nanowires, to larger concentration differences in different polytypes, which can be relevant for cubic-hexagonal homojunctions; (iv) ultrasmall diameters exhibit, regardless of the crystal phase, a pronounced surface segregation tendency for p-type dopants. Overall these findings shed light on the role of crystal phase in the doping mechanism at the nanoscale and could have a great potential in view of the recent experimental works on group IV nanowires polytypes. M.A. greatly acknowledges the Transnational Access Programme of the HPC-EUROPA3 (project HPC17PB9IZ). Part of the high-performance computing (HPC) resources for this project were granted by the Institut du developpement et des ressources en informatique scientifique (IDRIS) under the allocation A0040910089 via GENCI (Grand Equipement National de Calcul Intensif). This work was supported by the ANR HEXSIGE project (ANR-17-CE030-0014-01) of the French Agence Nationale de la Recherche. We also acknowledge financial support by the Ministerio de Economía, Industria y Competitividad (MINECO) under Grants FEDER-MAT2017-90024-P and FIS2015-64886-C5-4-P, the Severo Ochoa Centres of Excellence Program under Grant SEV-2015-0496, the Generalitat de Catalunya under Grants 2017 SGR 1506. S.O. acknowledges support/funding from University of Modena and Reggio Emilia under project ”FAR2017INTERDISC”. |
| Databáze: | OpenAIRE |
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