Correlated optical and structural analyses of individual GaAsP/GaP core-shell nanowires

C Himwas; S Collin; H-L Chen; G Patriarche; F Oehler; L Travers; O Saket; F H Julien; J-C Harmand; M Tchernycheva

doi:10.1088/1361-6528/ab1760

Correlated optical and structural analyses of individual GaAsP/GaP core-shell nanowires

Nanotechnology. 2019 Jul 26;30(30):304001. doi: 10.1088/1361-6528/ab1760. Epub 2019 Apr 9.

Authors

C Himwas¹, S Collin, H-L Chen, G Patriarche, F Oehler, L Travers, O Saket, F H Julien, J-C Harmand, M Tchernycheva

Affiliation

¹ Centre de Nanosciences et de Nanotechnologies, UMR 9001 CNRS, Univ. Paris Sud, Univ. Paris-Saclay, 10 Boulevard Thomas Gobert, F-91120 Palaiseau Cedex, France. Semiconductor Device Research Laboratory, Department of Electrical Engineering, Faculty of Engineering, Chulalongkorn University, 254 Phayathai Road, Bangkok 10330, Thailand.

PMID: 30965307
DOI: 10.1088/1361-6528/ab1760

Abstract

We report on the structural and optical properties of GaAs_0.7P_0.3/GaP core-shell nanowires (NWs) for future photovoltaic applications. The NWs are grown by self-catalyzed molecular beam epitaxy. Scanning transmission electron microscopy (STEM) analyses demonstrate that the GaAsP NW core develops an inverse-tapered shape with a formation of an unintentional GaAsP shell having a lower P content. Without surface passivation, this unintentional shell produces no luminescence because of strong surface recombination. However, passivation of the surface with a GaP shell leads to the appearance of a secondary peak in the luminescence spectrum arising from this unintentional shell. The attribution of the luminescence peaks is confirmed by correlated cathodoluminescence and STEM analyses of the same NW.