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Open Access Nano Idea

Influence of substrate orientation on exciton fine structure splitting of InAs/InP nanowire quantum dots

Michał Zieliński

Author Affiliations

Instytut Fizyki, UMK, Grudzia̧dzka 5, Toruń, 87-100, Poland

Nanoscale Research Letters 2012, 7:265  doi:10.1186/1556-276X-7-265

Published: 22 May 2012

Abstract

In this paper, we use an atomistic approach to investigate strain distributions, single particle and many body electronic properties of InAs/InP nanowire quantum dots with substrate orientation varying from [111] to high-index [119], and compared with [001] case. We show that single particle gap for high-index [11k] substrates is increased with respect to [111] and [001] cases, and oscillates with the substrate index due to faceting effects. Surprisingly, the overall shell-like structure of single particle states is preserved even for highly facetted, high-index substrates. On the contrary, we demonstrate that besides two limiting high-symmetry cases, [001] and [111], the bright exciton splitting varies strongly with substrate orientation. For [112]-oriented substrate, the fine structure splitting reaches maximum due to crystal lattice anisotropy despite fully cylindrical isotropic shape of nanowire quantum dot.

Keywords:
Nanowire quantum dots; Excitons; Fine structure splitting; Substrate orientation