The observation of strong visible photoluminescence (PL) from Molecular Beam Epitaxy (MBE) B-doped porous Si0.7Ge0.3 grown on p(-)-type Si wafers are reported. The porous layers were formed by an electrochemical etching process with a range of preparative conditions. A significant shift in the emission energy of porous Si0.7Ge0.3 grown on Si has been observed for various anodization conditions and for the temperature range 295-78 K. The PL emission energy has been found to remain almost unchanged on varying excitation energy, and to increase linearly with reciprocal temperature, The position of the PL emission, however, was observed to be strongly dependent upon the anodization current density and the duration of the etching process. The origin of visible PL of the porous MBE-SiGe films is interpreted by considering the quantum confinement effect, as in the interpretation of PL from porous Si, and the evolution of the SiGe Si-like band structure. (C) 1997 Elsevier Science S.A.