Structural and optical characteristics of porous GaN generated by electroless chemical etching

This article reports the structural and optical properties of porous GaN prepared by Pt assisted electroless chemical etching. The images of scanning electron microscopy revealed that the density of the pores increased with etching duration, however, the etching duration has no significant effect on the size and shape of the pores. The atomic force microscopy measurements exhibited that the surface roughness was increased with etching durations; however, for long etching duration, the increase of the surface roughness became insignificant. Raman spectra showed that the absence of two forbidden modes i.e. A1(TO) and E1(TO) in the as-grown sample was observed in some porous samples. Optical transmission measurements revealed that the increase of pore density would lead to the reduction of light transmission. The studies showed that the structural and optical properties of the GaN could be influenced by the porosity.