ZnSiGeP2 heteroepitaxial films will be grown by chemical beam epitaxy(CBE), and plasma-assisted CBE; SiO2/Si structures, and passivated Si reference surfaces will be synthesized by plasma-assisted processing and wet chemistry techniques for basic investigations of materials synthesis and processing phenomena, and for investigations of nonlinear optical(NLO) effects. The NLO studies will be conducted with ZnGeP2 bulk single crystals and ZnSiGeP2 heteroepitaxial films grown on Si, GaP and SiGe/Si substarates, and at SiO2/Si surfaces. These studies are expected to yield basic information relative to NLO mechanisms, and in particular their dependence on interfacial strain, and interfacial bonding chemistry. This information will then be used as a basis for the design of device structures, which will then be evaluated for potential applications. %%% This research is expected to advance the materials science in synthesis and processing of novel nonlinear optical materials with enhanced properties. This information will form the basis for evaluation of their performance advantages as optoelectronic circuit elements used in advanced computing, information processing, and telecommunications.