InGaAs/GaAs quantum dot (QD) structures are grown with As-4 and As-2 sources using molecular beam epitaxy (MBE). In0.3Ga0.7As and In0.4Ga0.6As QDs grown with an As-4 source have anisotropic shape, which is elongated to [1 (1) over tilde 0] direction, while QDs grown with an As-2 source have isotropic shape. These results are thought to result from the difference in the surface structures under As-4 and As-2 sources. QDs grown with an As-4 source have narrower photoluminescence (PL) linewidths and a shorter wavelength emission than those grown with an As-2 source. (c) 2006 Elsevier B.V. All rights reserved.