Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Gallium hydride vapor phase epitaxy of GaN nanowires | Zervos and Othonos Nanoscale Research Letters 2011 6 262 http content 6 1 262 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Gallium hydride vapor phase epitaxy of GaN nanowires Matthew Zervos1 and Andreas Othonos2 Abstract Straight GaN nanowires NWs with diameters of 50 nm lengths up to 10 pm and a hexagonal wurtzite crystal structure have been grown at 900 C on nm Au Si 001 via the reaction of Ga with NH3 and N2 H2 where the H2 content was varied between 10 and 100 . The growth of high-quality GaN NWs depends critically on the thickness of Au and Ga vapor pressure while no deposition occurs on plain Si 001 . Increasing the H2 content leads to an increase in the growth rate a reduction in the areal density of the GaN NWs and a suppression of the underlying amorphous a -like GaN layer which occurs without H2. The increase in growth rate with H2 content is a direct consequence of the reaction of Ga with H2 which leads to the formation of Ga hydride that reacts efficiently with NH3 at the top of the GaN NWs. Moreover the reduction in the areal density of the GaN NWs and suppression of the a-like GaN layer is attributed to the reaction of H2 with Ga in the immediate vicinity of the Au NPs. Finally the incorporation of H2 leads to a significant improvement in the near band edge photoluminescence through a suppression of the non-radiative recombination via surface states which become passivated not only via H2 but also via a reduction of O2-related defects. Introduction Group III-nitride III-N compound semiconductors such as GaN InN and AlN have been investigated intensively over the past decades in view of their successful application as electronic and optoelectronic devices 1 . In particular III-N semiconductors are attractive since their band-gaps vary between eV in InN 2 and eV in GaN 3 up to eV in AlN 4 allowing the band-gaps of AlxGa1-xN or InxGa1-xN to be tailored in between by varying x which
