The study of interfaces for both epitaxial and wafer-bonded systems draws from materials science, electrical engineering, and mechanical engineering and involves advanced materials characterization techniques. Low temperature wafer bonding has been leveraged to produce a wide array of materials combinations, most notably silicon-on-insulator structures. However, bonded interfaces can impact the electrical or thermal transport across such interfaces. In this presentation, we provide a few examples in semiconductor-based systems to address the ability to study and modify different, technologically important, interface combinations as a function of processing, such as annealing. The materials combinations primarily involve wide bandgap materials combinations including GaN|Si to b-Ga₂O₃ | SiC as well as bonding to single crystal diamond. In addition, we describe the role of the relative lattice orientation across semiconductor-semiconductor interfaces on transport properties and polarization engineering to producing high performance heterointerfaces. Our main goal is to be able to study and engineer the interfaces to optimize properties and ultimately, device performance.