Photo-voltaic effects are considered for semiconductors in which doping, energy gap and temperature are position-dependent. Formula derived for total current density contains four effects: (1) bulk photo-voltaic effect, (2) photo-voltaic effect resulting from inhomogeneity of mobilities, (3) thermo-photo-voltaic effect arising from combined photoconductivity and thermo-electric effects, (4) Seebeck thermo-electric effect. Numerical results shown in figures present relative values of these effects calculated for Ge-Si semiconductor material.