Morphology Control in As-Grown GaN Nanoporous Particles

The influence of different parameters, such as temperature, flow rate of NH 3, and pressure, in the crystal growth process of GaN micron-size nanoporous particles through the direct reaction of Ga and NH 3 has been studied. Temperature influences porosity and the coalescence of the individual pores. Flow rate of NH 3 influences the degree of nanoporosity of the particles. Pressure is the main parameter controlling the external shape of the particles by modulation of the crystal growth rate along or perpendicular to the c crystallographic direction. It also seems to play a role in controlling the size of the pores that can be obtained. Programmed and controlled changes in pressure during the growth experiment resulted in interesting nanoporous structures with benefits for extraction of light and fabrication of electrical contacts on these particles.