C-60 uniformly doped GaAs and C-60, Si codoped GaAs layers are grown on GaAs substrates by a migration enhanced epitaxy method. X-ray diffraction measurements indicate that the crystalline quality of the C-60 doped GaAs layers is not deteriorated until the concentrations of 1 x 10(19) cm(-3). In high-resolution transmission electron microscopy images, dark spots induced by the strain contrast are observed in C-60 uniformly doped GaAs layer and no dislocation is confirmed around the doped C-60 molecules. The electron energy-loss spectroscopy spectrum at the C-60 rich region coincides well with the results of pure C-60 crystals, indicating that unoccupied molecular orbitals of the C-60 molecules are active even in the GaAs lattices. Raman scattering peaks from C-60 molecules are obtained for the layers with high C-60 concentrations. At low temperatures, the photoconductivity peak around 1000 nm appears only in the C-60 doped GaAs layers, implying that the resonant excitation between C-60 traps and GaAs bands occur. (c) 2012 Elsevier B.V. All rights reserved.