We have grown GaAs layers by molecular beam epitaxy on Si(1 1 0) substrates with different tilted angles towards the [001] direction. The samples where characterized by atomic force microscopy (AFM), high resolution x-ray diffraction (HRXRD), transmission electron microscopy (TEM), and photoreflectance spectroscopy (PR). The full width at half maximum of the HRXRD reflection peaks and the surface roughness determined by AFM decreased as the off angle increased up to 6 degrees. ne increase in the crystal quality of the films was confirmed by the TEM measurements. The PR spectra showed the presence of oscillations above the GaAs band-gap signal associated to built-in internal electric fields. The built-in electric field strength and the GaAs band-gap energy values were obtained by employing the Franz-Keldysh model. We obtained band-gap energy values that suggest the presence of residual strains in the films.