Free standing c-GaN films grown by low-pressure metalorganic chemical vapor deposition on GaP (100) substrates

Gallium nitride (GaN) films were synthesized by low pressure metalorganic chemical vapor deposition on GaP (100) substrates. Samples were grown using three-step growth method, which includes a) a nitridation process of the GaP surface, b) the growth of a GaN buffer layer and c) the growth of the high-temperature epilayer. X-ray diffraction, Raman spectroscopy and FESEM and HRTEM were used to study the changes in the surface, which suggests that the cubic phase nucleation takes place during nitridation process and remained at the top surface, which results in preferential growth of c-GaN.