Role of Ga Surface Diffusion in the Elongation Mechanism and Optical Properties of Catalyst-Free GaN Nanowires Grown by Molecular Beam Epitaxy - Université Grenoble Alpes Accéder directement au contenu
Article Dans Une Revue Nano Letters Année : 2019

Role of Ga Surface Diffusion in the Elongation Mechanism and Optical Properties of Catalyst-Free GaN Nanowires Grown by Molecular Beam Epitaxy

Résumé

We have shown that both the morphology and elongation mechanism of GaN nanowires homoepitaxially grown by plasma-assisted molecular beam epitaxy (PA-MBE) on a [0001]-oriented GaN nanowire template are strongly affected by the nominal gallium/nitrogen flux ratio as well as by additional Ga flux diffusing from the side walls. Nitrogen-rich growth conditions are found to be associated with a surface energy-driven morphology and reduced Ga diffusion on the (0001) plane. This leads to random nucleation on the (0001) top surface and preferential material accumulation at the periphery. By contrast, gallium-rich growth conditions are characterized by enhanced Ga surface diffusion promoting a kinetically driven morphology. This regime is governed by a potential barrier that limits diffusion from the top surface toward nanowire side walls, leading to a concave nanowire top surface morphology. Switching from one regime to the other can be achieved using the surfactant effect of an additional In flux. The optical properties are found to be strongly affected by growth mode, with point defect incorporation and stacking fault formation depending on gallium/nitrogen flux ratio.
Fichier principal
Vignette du fichier
Revised manuscript - submitted.pdf (1.29 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-02269025 , version 1 (18-12-2020)

Identifiants

Citer

Marion Gruart, Gwenolé Jacopin, Bruno Daudin. Role of Ga Surface Diffusion in the Elongation Mechanism and Optical Properties of Catalyst-Free GaN Nanowires Grown by Molecular Beam Epitaxy. Nano Letters, 2019, 19 (7), pp.4250-4256. ⟨10.1021/acs.nanolett.9b00023⟩. ⟨hal-02269025⟩
108 Consultations
222 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More