An apparatus for reducing photodiode thermal gain coefficient includes a bulk semiconductor material having a light-illumination side. The bulk semiconductor material includes a minority charge carrier diffusion length property configured to substantially match a predetermined hole diffusion length value and a thickness configured to substantially match a predetermined photodiode layer thickness. The apparatus also includes a dead layer coupled to the light-illumination side of the bulk semiconductor material, the dead layer having a thickness configured to substantially match a predetermined thickness value and wherein an absolute value of a thermal coefficient of gain due to the minority carrier diffusion length property of the bulk semiconductor material is configured to substantially match an absolute value of a thermal coefficient of gain due to the thickness of the dead layer.