Carbon implantation effects on self-assembled Ge quantum dots (QDs) have been investigated. Carbon atoms were implanted at different dosage, 9.0 X 10(14), 4.5 x 10(15), and 9.0 x 10(15) ions/cm(2) using the same acceleration energy of 20 keV. A nominal amount, 6 monolayer (ML), of Ge was grown on the substrate at different growth temperatures ranging from 500 to 600 degrees C using solid source molecular beam epitaxy. The smallest Ge QDs with a 13 nm mean lateral diameter, a 1.2 nm mean height, and an areal density of 2.0 x 10(11) cm(-2) were obtained using the lowest dosage substrate at 550 degrees C. Raman measurement is carried out to investigate the optical phonons and strain. (c) 2007 Elsevier B.V. All rights reserved.