Search

Abstract: Surface topography of GaN layer grown on Si (111) using metalorganic chemical vapor deposition before and after etching were investigated by plan-view transmission electron microscopy and scanning electron microscopy. Different shape of etch pits appeared on GaN with different thickness, and typical pits which reflected the dislocation interaction always occurred at the junction of sub-grains. The mechanism was discussed. [Copyright &y& Elsevier]

Abstract: GaN was deposited on patterned c-plane sapphire (0001) wafers as the ELO technique without mask by metal organic chemical vapor deposition (MOCVD). The crystal structure and the growth mechanism were analyzed, this mechanism inhibited dislocations to extend to the surface of the epilayer and hollows between pits and epilayer released the stress of the material reducing the dislocation density. The properties of GaN layer were investigated by double crystal X-ray diffraction, atomic force microscopy, wet chemical etching and scanning electronic microscopy. The results proved that higher-quality GaN layer was received using this method. [Copyright &y& Elsevier]

In this paper, samples were prepared by co-implanting Dy and carbon ions into c-plane (0001) GaN films and a subsequent rapid thermal annealing at 800 °C. The room temperature magnetic properties of Dy and C co-implanted GaN samples were investigated by experiments and theoretical calculations. Dy and C co-implanted GaN samples had the larger room temperature magnetic moment than that of the Dy-implanted GaN. The calculated results showed that the spin polarization of C-2p electrons leads to the local magnetic moment due to the hybridization between Dy-4f electron states and C-2p electron, which explains the enhancement of magnetic moment in co-implanted GaN samples. Our results suggest that co-implantation is a potential approach to enhance the room temperature ferromagnetism. [ABSTRACT FROM AUTHOR]

Abstract: We report the growth of GaN epilayers on the sapphire substrate etched by MOCVD. Sapphire substrate is etched by H3PO4 and NaOH. The Raman scattering spectroscopy and photoetching analyses show that the substrate etched can effectively decrease the residual stress and the dislocations density in these epilayers. The X-ray diffraction analysis shows the process can reduce the value of the FWHM. Therefore, the quality of GaN epilayers should be improved by substrate etched. [Copyright &y& Elsevier]