High quality GaN layers grown by metalorganic chemical vapor deposition onSi(111) substrates

GaN layers-are grown onto silicon (111) substrates by metalorganic chemical vapor phase deposition (MOCVD). The X-ray and photoluminescence spectra as well as the surface :morphologies of the layers are comparable to the char acteristics of GaN layers grown on sapphire substrates. Linewidths of 610 a rcsec in the case of the GaN(0002) reflection in the X-ray omega-scan and 1 3 meV at 10 K for the dominant excitonic photoluminescence at 3.44 eV as we ll as a,surface roughness below 2nm (rms) are observed. The high quality ha s been achieved by a careful optimization of AlAs/AlN-buffer layers on the Si substrates.