InAs1-xSbx quantum structures grown on InP(001) by metalorganic vapor-phase epitaxy were investigated for a wide range of Sb content. InAs quantum dots (QDs) had an asymmetric shape elongated in the [110] direction. Inducing small Sb content (x = 0.06) reduced the size of QDs to around 30 nm with improved shape symmetry, revealing that the migration length of adatoms or incorporation probability at steps was reduced by Sb. As the Sb content increased further, the shape changed into quantum wires (QWRs) (x = 0.12, 0.39) with widths of 18-19 nm, and quantum wells (x = 0.70), which are related to the Sb surfactant effect. These results indicate that Sb has two competing functions in forming InAs1-xSbx quantum structures: the surfactant effect and the modification of kinetics of adatoms or energetics at steps. The Sb amount is a key factor in controlling the shape of those structures. (c) 2006 Elsevier B.V. All rights reserved.