Photoassisted Anodic Etching of Gallium Nitride

The first study of photo‐assisted anodic etching of unintentionally doped n‐GaN at room temperature is reported here. The electrolyte used is a mixture of buffered aqueous solution of tartaric acid and ethylene glycol. The etching rate varies from ∼20 Å/min to as high as 1600 Å/min. A systematic study shows that ( i ) the etch rate, as well as the surface roughness, increases with the current density; ( ii ) the etching rate is the highest when the pH of the electrolyte is ∼7; and ( iii ) the etching is faster when there is more ethylene glycol in the electrolyte solution.