A relatively simple technique for fabrication of GaAs-based quasi-three-dimensional photonic crystals has been investigated. Selective impurity-induced layer disordering and wet oxidation techniques are utilized. Fourier-transform infrared spectroscopy measurement reveals a stop band between 15 and 20 mu m for a sample with scattering center spacing of 6.3 mu m. Another narrow transmittance dip in observable in the wavelength range of 1.1-1.58 mu m, with an attenuation of 12 dB at 1.18 mu m. The process is reproducible and lends itself to integration with other optoelectronic and electronic devices on the same substrate.