Abstract: A single crystal thin film of the compound ZnSiXGe1-XN2 (where x can range from 0 to 1). This thin film single crystal can be disposed on a single crystal substrate made of, for example, sapphire, silicon carbide, lithium gallate or silicon with or without an additional GaN buffer layer grown on them. Alternately, a GaN single crystal thin film grown on any substrate can be used. In the case of sapphire, it can be R-plane so that the thin film has its c-axis lying within the thin film or A- or C-plane so that the thin film has its c-axis perpendicular to the substrate. The substrate could also be any substrate with a GaN single crystal thin film deposited on it. ZnSiXGe1-XN2 single crystal thin films can be made by the MOCVD method using suitable precursors, molar injection ratios, and substrate temperatures. It is possible to make various optical, electro-optical or electronic devices with the material, for example, a second harmonic generator emitting blue light.