Nanometer sized pores were formed for the first time on p-type InP surfaces by electrochemical anodic polarization in HF and HBr solutions in the dark. The surface structures were characterized with scanning electron microscopy (SEM), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and photo-luminescence (PL) measurements. It is found that the surface morphology strongly depends on the type of halogen acid present in the electrolyte, and that the anodized samples emit photoluminescence in the visible wavelength range. (C) 2004 Elsevier Ltd. All rights reserved.