Structural and optical properties of III-V nanowires and nanowire heterostructures grown by metalorganic chemical vapour deposition

We have investigated the structural and optical properties of III-V nanowires grown by metalorganic chemical vapour deposition. Binary GaAs, InAs and InP nanowires, and ternary InGaAs and AlGaAs nanowires, have been fabricated and characterised. A variety of axial and radial heterostructures have also been fabricated, including GaAs/AlGaAs core-multishell and GaAs/InGaAs superlattice nanowires. GaAs/AlGaAs core-shell nanowires exhibit strong photoluminescence as the AlGaAs shell passivates the GaAs nanowire surface reducing the surface nonradiative recombination. © 2007 IEEE.

Structural and optical properties of axial and radial heterostructure III-V nanowires grown by metalorganic chemical vapour deposition

We have investigated the structural properties and photoluminescence of novel axial and radial heterostructure III-V nanowires, fabricated by metalorganic chemical vapour deposition. Segments of InGaAs have been incorporated within GaAs nanowires, to create axial heterostructure nanowires which exhibit strong photoluminescence. Photoluminescence is observed from radial heterostructure nanowires (core-shell nanowires), consisting of GaAs cores with AlGaAs shells. Core-multishell nanowires, of GaAs cores clad in several alternating layers of thick AlGaAs barrier shells and thin GaAs quantum well shells, exhibit a blue-shifted photoluminescence peak arising from quantum confinement effects. © 2006 Crown Copyright.

Mechanical and fracture properties of cement-based bi-materials after thermal cycling

This study investigates the effect of thermal cycles on the fracture properties of the cement-based bi-materials. Sixty eight cubes were exposed to a varied number of 24-hour thermal cycles ranging from 0 to 90 and subsequently were tested in a wedge splitting configuration. The mechanical and fracture properties of normal strength and high strength concretes are substantially improved after 30 thermal cycles, but less so after 90 thermal cycles both in isolation and when bonded to an ultra high-performance fibre-reinforced cement-based composite. © 2009 Elsevier Ltd. All rights reserved.