Simple wet-etching technology for GaN using an electrodeless photo-assisted electrochemical reaction with a luminous array film as the UV source

Abstract

A simple setup for electrodeless photo-assisted electrochemical (PEC) etching was discussed from the viewpoint of the experimental geometry, in which the sample was dipped into the electrolyte under ultraviolet (UV) irradiation. Sulfate radicals () were produced from K2S2O8 with UV light as the oxidizing agent; this consumed the extra UV photogenerated electrons, making it electrodeless. The transmittances were measured for various concentrations of K2S2O8 (aq.) to adjust the electrolyte depth. The effect of tetramethylammonium hydroxide post-treatment was also examined. The results indicate that damage-free PEC etching is feasible for everyone, even those who are not familiar with electrochemistry.