Self-organized dots of CdTe and Cd1-xMnxTe (x = 0.06) were fabricated on the Zn1-yCdyTe (1 0 0) surface by MBE. The dot formation on ZnTe was not different between CdTe and Cd1-xMnxTe but different features appeared with the increase of y. In CdTe dots, the density was decreased continuously with y and the size was increased, in qualitative accordance with the decrease of the lattice mismatch ratio between CdTe and Zn1-yCdyTe. On the other hand, the dot formation of Cd1-xMnxTe dots was little dependent on y; the density was almost constant and the size was increased to only a little extent. In photoluminescence (PL) measurements on capped dots, the energies of the excitonic emission were red-shifted with y in both CdTe and Cd1-xMnxTe dots. The PL spectra from Cd1-xMnxTe quantum dots showed well-defined splitting into two lines at low temperatures less than 10 K and it was found that the: Zeeman shift of the two lines was much different. (C) 2001 Elsevier Science B.V. All rights reserved.