Characterization of GaN layers grown on porous silicon

This work reports the first successful results of the growth of GaN on a porous silicon (PS) substrate. GaN layers have been grown on PS substrates by metalorganic vapour phase epitaxy (MOVPE) at atmospheric pressure. The growth rate (measured by laser reflectometry) was found to be dependent on the growth temperature. The surface morphology and crystallinity of the GaN films were characterized by atomic force microscopy (AFM), and X-ray diffraction (XRD). I–V and C–V characteristics of the GaN/PS structure measured at room temperature are reported. We found that the GaN/PS/Si heterojunction forms a diode-like structure with a rather good rectification behaviour.