Out-of-plane Ga2Se3nanowires are grown bymolecular beam epitaxy via Au-assisted heterovalent exchangereaction on GaAs substrates in the absence of Ga deposition. It isshown that at a suitable temperature around 560°C the Au-decorated GaAs substrate releases Ga atoms, which react with theincoming Se and feed the nanowire growth. The nanowirecomposition, crystal structure, and morphology are characterizedby Raman spectroscopy and electron microscopy. The growthmechanism is investigated by X-ray photoelectron spectroscopy.We explore the growth parameter window andfind an interestingeffect of shortening of the nanowires after a certain maximumlength. The nanowire growth is described within a diffusiontransport model, which explains the nonmonotonic behavior of thenanowire length versus the growth parameters. Nanowire shortening is explained by the blocking of Ga supply from the GaAssubstrate by thick, in-plane worm-like Ga2Se3structures, which grow concomitantly with the nanowires, followed by backwarddiffusion of Ga atoms from the nanowires down to the substrate surface.
Ga2Se3Nanowires via Au-Assisted Heterovalent Exchange Reactionon GaAs
Niloofar Haghighian;Faustino Martelli;Valentina Mussi;Alfonso Franciosi;Silvia RubiniUltimo
2020
Abstract
Out-of-plane Ga2Se3nanowires are grown bymolecular beam epitaxy via Au-assisted heterovalent exchangereaction on GaAs substrates in the absence of Ga deposition. It isshown that at a suitable temperature around 560°C the Au-decorated GaAs substrate releases Ga atoms, which react with theincoming Se and feed the nanowire growth. The nanowirecomposition, crystal structure, and morphology are characterizedby Raman spectroscopy and electron microscopy. The growthmechanism is investigated by X-ray photoelectron spectroscopy.We explore the growth parameter window andfind an interestingeffect of shortening of the nanowires after a certain maximumlength. The nanowire growth is described within a diffusiontransport model, which explains the nonmonotonic behavior of thenanowire length versus the growth parameters. Nanowire shortening is explained by the blocking of Ga supply from the GaAssubstrate by thick, in-plane worm-like Ga2Se3structures, which grow concomitantly with the nanowires, followed by backwarddiffusion of Ga atoms from the nanowires down to the substrate surface.File | Dimensione | Formato | |
---|---|---|---|
Ga2Se3 Rubini_rev.pdf
accesso aperto
Tipologia:
Documento in Post-print
Licenza:
Altro tipo di licenza
Dimensione
1.97 MB
Formato
Adobe PDF
|
1.97 MB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.