Si-doped self-assembled InAs quantum-dot samples were grown, and the influences of doping on the structural and optical properties of quantum dots were investigated. As Si doping concentrations increased, increased size, reduced areal density, and broadened size distributions of quantum dots were observed. Photoluminescence spectra of Si-doped quantum dots showed that the peaks of ground state transitions shifted with varied doping concentrations while, the peak positions of wetting layers were unchanged. Photoluminescence intensities of excited state transitions of Si-doped quantum dots and of wetting layers were reduced as Si concentration increased. (c) 2005 American Vacuum Society.