UV laser-induced nanostructured porous oxide in GaAs crystals

Laser processing is an important tool for inducing local topographical and chemical changes on the surface of technologically important materials to facilitate various device fabrication procedures or to favor chemical reactions. Here, we report that irradiation of GaAs crystal surfaces with c.w. UV laser radiation (λ = 244 nm) in ambient conditions produces a well defined layer of porous oxide with a thickness up to ∼0.4 μm. Under certain laser irradiation conditions the oxidized layer appears to self-organize into periodic features, collectively known as laser-induced periodic surface structures (LIPSS). The topography and composition of the laser grown surface oxide layer is investigated.