Hydroxyl-oriented adsorption on concaved spherical MCM-48 particles for the formation of GaN nanorings

GaN nanorings are obtained at low temperature via a MCM-48-templated solvothermal approach. A hydroxyl-oriented adsorption mechanism for the formation of nanorings on the concaved surface of spherical MCM-48 particles is suggested. Room-temperature photoluminescence (PL) spectrum of the GaN samples shows a broad BL band centered at 397 nm (3.13 eV), which is ascribed to the defects or surface states.