Photo-assisted anodic etching of GaN films in NaOH electrolyte with Cl ions

Photo-assisted anodic etching of high quality n-GaN films grown by metalorganic chemical vapour deposition (MOCVD) on sapphire substrate using sodium hydroxide (NaOH) electrolyte at room temperature is reported. It is found that the presence of chloride ions in the NaOH electrolyte accelerates the rate of photo-assisted anodic etching of GaN films. The effect of adding chloride ions in the NaOH electrolyte is to reduce the extent of the formation of gallium oxide layer on the surface. It seems that the presence of chloride ions in the NaOH electrolyte plays an important role in the photo-assisted anodic etching of n-GaN films.