A modified horizontal gradient-freeze (GF) technique with quasi-double parabolic temperature profile has been developed for the growth of Si-doped GaAs crystals. Using this technique and taking measures to prevent wetting of the quartz boat by the GaAs melt, dislocation-free (DF) Si-doped GaAs single crystals with <111>B and <211>B oriented seeds covering the carrier concentration (n) range of 1.8 × 1017ȁ7.6 × 1018 cm-3 have been successfully grown. A preliminary study has been made of the homogeneities of the crystals. It is suggested that the SiGaVGa complex could play a role in influencing the homogeneity and dislocation density (EPD) of Si-doped crystals.