MOCVD growth of cubic gallium nitride: Effect of V/III ratio

We have grown cubic GaN on GaAs(001) substrates by MOCVD using a double ste p process with a buffer deposition at 400 degrees C. The purpose of the buf fer deposited at very low temperature is to prevent GaAs decomposition at g rowth temperature. We have focused on the effect of the NH3/TEGa molar rati o on the growth of this metastable phase. We have assessed the crystalline quality using X-ray diffraction in the theta-2 theta mode, and have used lo w temperature (2 K) PL for evaluating the optical properties of the GaN fil ms. We found an optimum V/III ratio of 1250 at the growth temperature of 80 0 degrees C.