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 degrees 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 degrees 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 degrees 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. (C) 2014 Elsevier Ltd. All rights reserved.