In this study, nanoporous structures on In0.08Ga0.92N/AlN/Si thin films with a thickness of 1 µm were synthesized by photoelectrochemical etching technique at various etching durations. The structural and optical properties of the pre- and post-etched thin films were investigated. The field emission scanning electron microscope images and X-Ray diffraction measurements revealed that the films pre-etched thin film has a sufficiently smooth surface over a large region with wurtzite structure. The roughness increased with an increase in etching duration. The photoluminescence emission peaks had a blue shift phenomenon for the post-etched films at room temperature, compared with the pre-etched film. The photoluminescence intensities of porous InGaN structures were enhanced when the nanoporous structure was formed.