  Strained nanowires with varying InAs/InP core-shell thicknesses were grown
using Chemical Beam Epitaxy. Microphotoluminescence spectroscopy, performed at
low temperature, was then used to study the optical properties of single wires.
Emission from the InAs core was observed and its dependence on the shell
thickness/core diameter ratio was investigated. We found that it is possible to
tune the emission energy towards 0.8 eV by controlling this ratio. We have
compared the measured energies with calculated energies. Our findings are
consistent with the wires having a hexagonal crystal structure.
