Formation of GaN Nanorods in Monodisperse Spherical Mesoporous Silica Particles

Abstract

Gallium-nitride nanorods with a diameter of 15–40 nm and length of 50–150 nm are synthesized in monodisperse spherical mesoporous silica particles (MSMSPs) by high-temperature annealing of the Ga2O3 precursor in ammonia. The template material (a-SiO2) is selectively removed by etching the composite MSMSP/GaN particles with HF to give individual GaN nanorods. It is shown that the size of the GaN nanorods substantially exceeds the pore size of the MSMSPs (diameter ~3 nm, length ~10 nm). A possible mechanism by which GaN nanorods are formed is proposed. Redistribution of the material within the composite MSMSP/GaN particles possibly occurs via the surface diffusion of gaseous molecules within mesopores and via the diffusion of Ga and N atoms in a-SiO2.