Both the density and the ordering of InP quantum dots (QDs) grown on In0.48Ga0.52P/GaAs are controlled through the growth conditions. The control of the alignment of the QDs is achieved by determining the morphology of the In0.48Ga0.52P buffer through its growth temperature. For buffer layer growth temperatures near 470 degrees C, an undulated surface results, which act as a template for QDs aligned along the undulation ridges. Lower buffer layer growth temperatures near 440 degrees C result in smooth buffer layers and homogeneously distributed QDs: the density of the QDs is controlled by changing the growth rate of InP. Ultra-low density QDs are achieved (1 dot per mu m(2)) by reducing the InP growth rate down to 0.01 ML/s. Micro-photoluminescence measurements reflect the low density of the QDs. Because InP/In0.48Ga0.52P QDs are promising photon sources for device applications with emission in the spectral window of highest Si-based detector efficiency, control of their ordering and density entirely through growth conditions aids in the development of a number of applications. (C) 2011 Elsevier B.V. All rights reserved.