NOVELTY - Fabricating a semiconductor layer involves providing a substrate (1104) having a crystalline surface with a known lattice parameter (a); and growing a crystalline semiconductor layer on the crystalline substrate surface by coincident site lattice matched epitaxy, without any buffer layer between the crystalline semiconductor layer and the crystalline surface of the substrate, where the crystalline semiconductor layer is prepared to have a lattice parameter (a') that is related to the lattice parameter (a).    USE - For fabricating a semiconductor layer used in electronic device (claimed) selected from solid state lighting device, light emitting diode (LED), a solid state laser, a photovoltaic device, solar cell, transistor, sensor.    ADVANTAGE - The method provides defect free crystalline form; and is inexpensive method.    DETAILED DESCRIPTION - Fabricating a semiconductor layer involves providing a substrate (1104) having a crystalline surface with a known lattice parameter (a); and growing a crystalline semiconductor layer on the crystalline substrate surface by coincident site lattice matched epitaxy, without any buffer layer between the crystalline semiconductor layer and the crystalline surface of the substrate, where the crystalline semiconductor layer is prepared to have a lattice parameter (a') that is related to the lattice parameter (a). The substrate is MgAl2O4 (spinel); or one of C, Si, Ge, Sn and their alloys. The substrate has a diamond cubic structure or a zinc blended structure. INDEPENDENT CLAIMS are included for following:    (1) fabricating a semiconductor device involving providing a substrate having a crystalline surface with a known lattice parameter (a); growing a crystalline semiconductor layer on the crystalline substrate surface by coincident site lattice matched epitaxy, without any buffer layer between the crystalline semiconductor layer and the crystalline surface of the substrate, where the crystalline semiconductor layer is prepared to have a lattice parameter (a') that is related to the lattice parameter (a); and epitaxially growing at least one subsequent crystalline semiconductor layers on the first crystalline semiconductor layer; and    (2) an electronic device comprising a substrate having a crystalline surface with a known lattice parameter (a); a crystalline semiconductor layer grown on the crystalline substrate surface by coincident site lattice matched epitaxy, without any buffer layer between the crystalline semiconductor layer and the crystalline surface of the substrate, where the crystalline semiconductor layer is prepared to have a lattice parameter (a') that is related to the lattice parameter (a).    DESCRIPTION OF DRAWING(S) - The figure shows view of solar cell device.    Solar cell (1102)    Substrate (1104)    Germanium junction (1105)    Indium gallium nitride junction (1106)