The authors have investigated the growth of dots/wires on InP substrates by tuning the In(Ga, Al)As compositions for dots/wires and buffer layers. Dots and wires with compositions including InAs, In0.95Al0.05As, In0.95Ga0.05As, and In0.90Ga0.10As were grown on In0.53Ga0.26Al0.21As and In0.52Al0.48As buffer layers, respectively. In(Ga)As nanostructure grown on InAlAs ternary buffer layer forms elongated dots along the [0-11] direction. On the other hand, In0.95Ga0.05As and In0.90Ga0.10As nanostructures grown on InGaAlAs buffer layer form quantum wire arrays of high uniformity. 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 10 K. For the growth of In0.95Al0.05As nanostructures, dot formations are observed on the InAlAs and InGaAlAs buffer layers. (C) 2008 American Vacuum Society.