We have investigated the growth of InGaAs wires on InP substrates by tuning the Ga composition. Nanostructures including InAs, In0.95Ga0.05As, In0.90Ga0.10As, and In0.85Ga0.15As were grown on In0.53Ga0.26Al0.21As buffer layers. For the growth of InAs nanostructures, elliptical quantum dots are observed. As we add Ga composition to the nanostructures, quantum wires arrays along the [0 (1) over bar1] direction are formed for In0.95Ca0.05As and In0.90Ga0.10As nanostructures, and the In0.85Ga0.15As nanostructure shows a dash-wire morphology. The In0.90Ga0.10As quantum wires have a photoluminescence spectrum of emission peak at lambda similar to 1680 nm and a narrow full-width at half-maximum of 65 meV at 10K. The In0.90Ga0.10As quantum wires show a high emission polarization anisotropy of 47%. (C) 2008 Elsevier B.V. All rights reserved.