Photochemical pattern on p-type GaAs

Abstract A photochemical pattern on p-type GaAs has been realized with an electrodeless system. The illuminated zone appears to be above the surface whereas it is etched on n-type sample. The electrolyte is an acidic solution containing Fe 3+ as an oxidizing agent. This solution reacts with the material and particularly with As atom under light leading to As 4 O 6 growth.