Abstract:

We report the first formation of arrays of InN nanorods inside the nanoscale channels of mesoporous silica SBA-15. In(NO₃)₃ dissolved in methanol was incorporated into SBA-15 powder without prior pore surface functionalization. Formation of InN nanorod arrays was carried out by ammonolysis at 700 °C for 8 h. The final products have been characterized by FT-IR spectra, ²⁹Si MAS NMR spectra, Raman spectra, XRD patterns, TEM images, nitrogen adsorption–desorption isotherm measurements, and optical spectroscopy. The freestanding InN nanorods observed after silica framework removal with HF solution show diameters of 6–7.5 nm and lengths of 25–50 nm. Formation of a trace amount of In₂O₃ was also verified. The InN nanorods exhibit a broad band centered at around 550–600 nm, and a band gap energy of 1.5 eV was determined. No light absorption in the near-IR region was measured. The nanorods give a weak emission band centered at around 600 nm. These optical properties are believed to be related to the possible incorporation of oxygen during InN nanorod synthesis.