Role of pre-annealing treatment in improving the porosity of gallium nitride on cubic silicon (100) substrate

This report describes the improved properties of porous gallium nitride (GaN) via pre-annealing treatment using a conventional furnace system. Prior to this work, non-porous GaN samples were annealed at the temperature of 600–1000 °C in order to rise the quality of the samples. From the microscopic, structural and optical measurements, the optimum annealing temperature was found to be 800 °C. Next, the sample that was annealed at the optimum temperature was fabricated into a porous structure by using an electrochemical etching technique. The characteristic of the porous GaN was then investigated by observing its morphology and crystallography properties. For a comparative analysis, a porous GaN sample without the annealing treatment and a porous GaN sample that was then annealed at 800 °C (post-annealing treatment) were also prepared. It was found that the pre-annealing treatment promotes a better quality in porosity of the GaN than other counterparts.