GaAs layers have been grown on (100) semi-insulating GaAs by close-spaced vapor transport having used atomic hydrogen as the transport agent and different source-substrate spacers thickness. The surface morphology of these films has been observed by scanning electron microscopy, and the elemental composition determined by energy dispersive spectroscopy. The effect of varying the spacer thickness on the crystalline structure quality has been analyzed by the photoluminescence, x-ray diffraction and micro-Raman techniques. Measurements by these techniques show that the variation of the source-substrate spacer thickness has an effect on the crystalline quality, growth rate, impurity types, and on the surface morphology of the deposited GaAs.