GaN decomposition after high-energy ball milling and its transformation to BN hollow spheres in annealing samples doped with B

Abstract

In this work, GaN powders doped with B and Si were treated by high-energy ball milling, and subsequently, annealing at different temperatures. Transmission electron microscopy (TEM) observations showed the in-situ GaN decomposition in the undoped GaN specimen milled for 5 h. TEM also revealed that the chemical decomposition of GaN was more affected in samples doped with B. Thermo-gravimetric analysis indicates that an undoped GaN specimen decomposes at 1120 °C, Si-doped GaN samples disintegrate at 1150 °C, and finally, B-doped GaN samples decompose at the lower temperature of 940 °C. TEM and SEM results show that the annealing treatment of the as-milled B-doped GaN samples at 1150 °C for 15 min leads to the GaN decomposition and BN hollow nanostructures formation under an N2 atmosphere. The synthesized product consists of mesoporous powders with variable particle sizes from 500 nm to 1 μm having variable cavities in the range from 60 nm to 800 nm.