Optical properties of novel GaN 3D structures grown by metal-organic chemical vapor deposition (MOCVD)

Optical properties of novel micrometer-size Ga and GaN three-dimensional structures obtained by the metal-organic chemical vapour deposition (MOCVD) technique are presented in this letter. These structures are obtained as metallic three dimensions (3D) micrometer-size objects on an appropriate substrate by metalorganic (TMGa) pyrolisis and then GaN transformed on annealing under NH3 atmosphere at 650-750degreesC. These 3D GaN structures are analysed by optical means, using two-photon excitation (800 nm) and by UV Hg lamp fluorescent spectroscopy techniques, adapted to two-optical-microscopes apparatus. Very intense and blue/yellow light emission is observed from these 3D structures under 800 nm two-photon laser excitation and under UV Hg lamp excitation.