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Báo cáo hóa học: " Epitaxial Catalyst-Free Growth of InN Nanorods on c-Plane Sapphire"

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: Epitaxial Catalyst-Free Growth of InN Nanorods on c-Plane Sapphire | Nanoscale Res Lett 2009 4 532-537 DOI 10.1007 s11671-009-9276-z NANO EXPRESS Epitaxial Catalyst-Free Growth of InN Nanorods on c-Plane Sapphire I. Shalish G. Seryogin W. Yi J. M. Bao M. A. Zimmler E. Likovich D. C. Bell F. Capasso V. Narayanamurti Received 24 December 2008 Accepted 9 February 2009 Published online 27 February 2009 to the authors 2009 Abstract We report observation of catalyst-free hydride vapor phase epitaxy growth of InN nanorods. Characterization of the nanorods with transmission electron microscopy and X-ray diffraction show that the nanorods are stoichiometric 2H-InN single crystals growing in the 0001 orientation. The InN rods are uniform showing very little variation in both diameter and length. Surprisingly the rods show clear epitaxial relations with the c-plane sapphire substrate despite about 29 of lattice mismatch. Comparing catalyst-free with Ni-catalyzed growth the only difference observed is in the density of nucleation sites suggesting that Ni does not work like the typical vapor-liquid-solid catalyst but rather functions as a nucleation promoter by catalyzing the decomposition of ammonia. No conclusive photoluminescence was observed from single nanorods while integrating over a large area showed weak wide emissions centered at 0.78 and at 1.9 eV. Keywords InN Nanorods Nanowires Epitaxial growth Sapphire Catalyst-free Ni I. Shalish El G. Seryogin W. Yi J. M. Bao M. A. Zimmler E. Likovich D. C. Bell F. Capasso V. Narayanamurti Harvard University Cambridge MA 02138 USA e-mail shalish@seas.harvard.edu I. Shalish Ben Gurion University Beer Sheva Israel Present Address J. M. Bao University of Houston Houston TX 77004 USA Introduction InN marks the lower bandgap limit achievable within the group III-nitride semiconductor family. To date it has also been the most difficult-to-grow among that family mainly because at its growth temperature InN decomposes almost as readily as ammonia. Incorporation of In into GaN has also been difficult .