Poster De Conférence Année : 2015

Quantum confinement effect in InAs/InP quantum dot nanowires (QD-NWs) grown on silicon

Résumé

We study the optical properties of InAs/InP QD-NWs grown on silicon by solid source Molecular Beam Epitaxy (ssMBE) using the Vapor-Liquid-Solid (VLS) method [1,2]. The investigation of this material system enables us to tune the emission wavelength of the NWs into the telecommunication bands. We aim at VLS growth of vertically standing wurtzite InP NWs on Si(111) for a good control of the insertion of InAs QDs and the NW shape. We show that an in-situ deposition at 500°C of a gold-indium (Au-In) alloy as catalyst leads to droplets which do not react with the Si substrate and to vertical NWs, whereas an alloy is formed with the Si substrate at higher temperature leading to inclined NWs. The first minute of the NW growth is then investigated step by step by TEM measurements to follow the formation of the pyramid-shaped pedestal which was evidenced prior to the NW growth. A high degree of verticality was thus obtained ensuring a cylindrical symmetry for the QD-NWs during axial or radial growth which is necessary to reach a good waveguide behavior. Growth conditions were then optimized to control the structural quality and shape of InAs QDs inserted into the InP NWs. The purity of the wurtzite structure for the QD-NWs was confirmed by TEM and PL measurements. Then, the VLS growth method allows us to control the InAs QD height to diameter ratio H/D with sharp interfaces as also revealed by TEM measurements (Fig.1). When the ratio is in the order of 1 with height and diameter typically in the 10-14 nm range, low temperature PL measurements performed on QD-NW populations revealed a single peak at 0.84 eV. For smaller ratios, the carriers are mainly confined by the QD height, and the PL spectra presented multiple peaks which are attributed to monolayer fluctuation in the InAs QD height (Fig.2).

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Dates et versions

hal-01489631 , version 1 (14-03-2017)

Identifiants

  • HAL Id : hal-01489631 , version 1

Citer

Amaury Mavel, Philippe Regreny, G. Patriarche, Bruno Masenelli, Nicolas Chauvin, et al.. Quantum confinement effect in InAs/InP quantum dot nanowires (QD-NWs) grown on silicon. Nanowire week 2015, Oct 2015, Barcelone, Spain. 2015. ⟨hal-01489631⟩
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