Growth optimization and characterization of regular arrays of GaAs/AlGaAs core/shell nanowires for tandem solar cells on silicon

With a band gap value of 1.7 eV, Al0.2Ga0.8As is one of the ideal III-V alloys for the development of nanowire-based Tandem Solar Cells on silicon. Nevertheless, growing self-catalysed AlGaAs nanowires on silicon by solid-source molecular beam epitaxy is a very difficult task due to the oxidation of...

Full description

Saved in:
Bibliographic Details
Published in:Nanotechnology 2019-02, Vol.30 (8), p.84005-084005
Main Authors: Vettori, M, Piazza, V, Cattoni, A, Scaccabarozzi, A, Patriarche, G, Regreny, P, Chauvin, N, Botella, C, Grenet, G, Penuelas, J, Fave, A, Tchernycheva, M, Gendry, M
Format: Article
Language:English
Subjects:
core/shell structures
EBIC
Engineering Sciences
heterogeneous integration
Materials
Micro and nanotechnologies
Microelectronics
nanowires
ordered arrays
radial junction
self-catalysed
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:With a band gap value of 1.7 eV, Al0.2Ga0.8As is one of the ideal III-V alloys for the development of nanowire-based Tandem Solar Cells on silicon. Nevertheless, growing self-catalysed AlGaAs nanowires on silicon by solid-source molecular beam epitaxy is a very difficult task due to the oxidation of Al adatoms by the SiO2 layer present on the surface. Here we propose a nanowire structure including a p.i.n radial junction inside an Al0.2Ga0.8As shell grown on a p-GaAs core. The crystalline structure of such self-catalysed nanowires grown on an epi-ready Si(111) substrate (with a thin native SiO2 layer) was investigated by transmission electronic microscopy and photoluminescence. I(V) measurements performed on single nanowires have shown a diode-like behaviour corresponding to the radial p.i.n junction inside the Al0.2Ga0.8As shell. Moreover, a current generation under the electron beam was evidenced over the entire radial junction along the nanowires by means of electron beam induced current (EBIC) microscopy. The same structure was reproduced on patterned substrates with a SiO2 mask, producing an ordered hexagonal array. High and uniform yields from 83% to 87% of vertical nanowires were obtained on 0.9 × 0.9 cm2 patterned areas. EBIC mapping performed on these nanowires confirmed the good electrical properties of the radial junction within the nanowires.
ISSN:0957-4484
1361-6528
DOI:10.1088/1361-6528/aaf3fe