GaAs has been grown on Ge substrate oriented 6 degrees off towards (1 1 0) by atmospheric pressure MOVPE. Various growth rates and growth temperatures were tried to get device quality epitaxial layers suitable for solar cell applications. It was observed that the growth temperatures and the growth rates affect the surface morphology, optical and interface properties and crystalline quality of the epitaxial layers. This was studied using optical microscope, photo luminescence, photovoltage measurements, ECV and double crystal X-ray diffractometry.