Wet etching of dilute nitride GaInNAs, GaInNAsSb, and GaNAsSb alloys lattice-matched to GaAs

We have studied the etching of GaInNAs, GaInNAsSb, and GaNAsSb alloys by NH4OH, H2SO4, and H3PO4 based solutions. NH4OH based solutions resulted in smooth surface, while other solutions created rougher and granular surfaces. The etch rates were found to increase with the Sb content. For GaInNAs, x-ray photoelectron spectroscopy revealed the enrichment of In on the etched surfaces, indicating In or In oxides having a smaller removal rate compared to Ga or Ga oxides. The enrichment of In was associated with smoother surfaces after etching and an enhanced photoluminescence caused by lower surface recombination due to reduced surface state density.