Crystalline, Phononic and Electronic properties of Heterostructured Polytypic Ge Nanowires by Raman Spectroscopy

Fasolato, Claudia and De Luca, Marta and Djomani, Doriane and Vincent, Laetitia and Renard, Charles and Di Iorio, Giulia and Paillard, Vincent and Amato, Michele and Rurali, Riccardo and Zardo, Ilaria. (2018) Crystalline, Phononic and Electronic properties of Heterostructured Polytypic Ge Nanowires by Raman Spectroscopy. Nano letters, 18 (11). pp. 7075-7084.

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Official URL: https://edoc.unibas.ch/69006/

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Semiconducting nanowires (NWs) offer the unprecedented opportunity to host different crystal phases in a nanostructure, which enables the formation of polytypic heterostructures where the material composition is unchanged. This characteristic boosts the potential of polytypic heterostructured NWs for optoelectronic and phononic applications. In this work, we investigate cubic Ge NWs where small (∼20 nm) hexagonal domains are formed due to a strain-induced phase transformation. By combining a nondestructive optical technique (Raman spectroscopy) with density-functional theory (DFT) calculations, we assess the phonon properties of hexagonal Ge, determine the crystal phase variations along the NW axis, and, quite remarkably, reconstruct the relative orientation of the two polytypes. Moreover, we provide information on the electronic band alignment of the heterostructure at points of the Brillouin zone different from the one (Γ) where the direct band gap recombination in hexagonal Ge takes place. We demonstrate the versatility of Raman spectroscopy and show that it can be used to determine the main crystalline, phononic, and electronic properties of the most challenging type of heterostructure (a polytypic, nanoscale heterostructure with constant material composition). The general procedure that we establish can be applied to several types of heterostructures.
Faculties and Departments:05 Faculty of Science > Departement Physik > Physik > Experimental Material Physics (Zardo)
UniBasel Contributors:Zardo, Ilaria and Fasolato, Claudia and De Luca, Marta and Di Iorio, Giulia
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Chemical Society
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:08 Feb 2020 15:07
Deposited On:27 Feb 2019 14:50

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