Formation of Arrays of Gallium Nitride Nanorods within Mesoporous Silica SBA-15

• Published in: The journal of physical chemistry. B 2005-09, Vol.109 (38), p.17842-17847
• Main Authors: Yang, Cheng-Tzu, Huang, Michael H
• Format: Article
• Language: English
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp052228k

We report the first formation of arrays of GaN nanorods inside the nanoscale channels of mesoporous silica SBA-15. GaCl3 dissolved in toluene was incorporated into the methyl group-functionalized SBA-15 powder. The pore surfaces functionalized with methyl groups should facilitate the impregnation with GaCl3. Formation of GaN nanorod arrays within SBA-15 was carried out by heating the powder to 700 °C for 3 h under nitrogen atmosphere, followed by ammonolysis at 900 °C for 5 h. ε-Ga2O3, an unusual phase for Ga2O3, formed after the first thermal process and was converted into wurtzite GaN during ammonolysis. The final products have been characterized by FT-IR spectra, powder XRD patterns, TEM images and SAED patterns, EDS analysis, and nitrogen adsorption−desorption isotherm measurements to confirm the presence of GaN nanostructures. The nanorods are 6−7.5 nm in diameter, and can be a few hundreds of a nanometer in length to exhibit nanowire structure. Free-standing GaN nanorod arrays were revealed upon removal of the silica framework with HF solution. Optical characterization of the isolated GaN nanorod arrays shows a strong and sharp near band-edge emission at 375 nm, and two phonon-assisted donor−acceptor peaks at 395 and 415 nm. A broad but weak emission in the region of 335−360 nm due to the quantum confinement effect of short nanorods was observed.