In this paper, we describe the formation of colloidal Si/Ge semiconductor nano-particles by electrochemical etching of Ge quantum dots (GEDOT), Silicon-Germanium graded layers (GRADE) and Silicon-Germanium multi-quantum well (MQW) structures which are prepared on Silicon wafers using low pressure chemical vapor deposition (LPCVD) technique. The formation of Si/Ge nano-particles is verified by transmission electron microscope (TEM) images and photoluminescence (PL) measurements. The Si/Ge nano-particles obtained from GEDOT and GRADE structures, gave blue emissions, upon 250 nm, and 300 nm UV excitations. However, the nano-particles obtained from the MQW structure did exhibit various color emissions (orange, blue, green and red) upon excitation with 250 nm, 360 nm, 380 nm and 400 nm wavelength light.