Ultra-thin Si₃N₄ films were grown on Si(111) surface by radio frequency (RF)-N₂ plasma exposure at 900 °C with 1–1.2 sccm of a flux of atomic nitrogen. We discuss the effect of various conditions such as N₂ flow rate, nitriding time and RF power on the optical, chemical, and structural properties of a nitrided Si₃N₄ layer. The optical properties, surface morphology and chemical composition are investigated by using ellipsometry, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Cross-sectional TEM images show that an RF power of 350 W induced some damage to the Si(111) surface. The thickness of nitrided Si₃N₄ was measured to be about 5–7 nm. XPS results shown that the binding energy of Si 2p_3/2 located at 101.9 ± 0.1 eV is attributed to the Si–N bonds in the Si₃N₄ compound. Smooth Si₃N₄ ultra-thin films were obtained at a nitridation time close to 1 h with an RF power of 300 W, with a measured refractive index (n) nearly to 1.88 at 632 nm. The increase in refractive index with decreased RF-plasma power and nitrogen flow rate is probably attributed to the change in the stoichiometry of the film and less surface damage.

Hexagonal pyramid-like InN nanocolumns were grown on Si(111) substrates via radio-frequency (RF) metal–organic molecular beam epitaxy (MOMBE) together with a substrate nitridation process. The metal–organic precursor served as a group-III source for the growth of InN nanocolumns. The nitridation of Si(111) under flowing N₂ RF plasma and the MOMBE growth of InN nanocolumns on the nitrided Si(111) substrates were investigated along with the effects of growth temperature on the structural, optical, and chemical properties of the InN nanocolumns. Based on X-ray diffraction analysis, highly -oriented, hexagonal InN nanocolumns were grown on the nitride Si(111) substrates. To evaluate the alignment of arrays, the deviation angles of the InN nanocolumns were measured using scanning electron microscopy. Transmission electron microscopy analysis indicated that the InN nanocolumns were single-phase wurtzite crystals having preferred orientations along the c-axis. Raman spectroscopy confirmed the hexagonal structures of the deposited InN nanocolumns.