Electroluminescence characterization of cubic gallium nitride p-n junctions grown on SiC/Si substrates by MBE

The electroluminescence (EL) properties of prospective cubic gallium nitride p-n junctions grown by molecular beam epitaxy (MBE) are studied. The samples were deposited on a 3 mu m thick silicon carbide: layer grown by chemical vapor deposition (CVD) on an n(+) silicon substrate. At room temperature, visible and UV electroluminescence are obtained for V = 2.5 V under de conditions. At low temperatures only UV luminescence is observed. This low temperature luminescence is mostly given by shallow donor-acceptor and band edge transitions. The activation at increasing temperatures of a visible green-blue electroluminescent band could be explained by the thermal activation of Mg deep states. Our results indicate that the MBE cubic gallium nitride material is a promising alternative for the fabrication of light emitters on silicon compatible substrates.