Various embodiments of the present invention are related to microresonator systems that can be used as a laser, a modulator, and a photodetector and to methods for fabricating the microresonator systems. In one embodiment, a microresonator system comprises a substrate having a top surface layer, at least one waveguide embedded within the substrate, and a microdisk having a top layer, an intermediate layer, a bottom layer, current isolation region, and a peripheral annular region. The bottom layer of the microdisk is in electrical communication with the top surface layer of the substrate and is positioned so that at least a portion of the peripheral annular region is located above the at least one waveguide. The current isolation region is configured to occupy at least a portion of a central region of the microdisk and has a relatively lower refractive index and relatively larger bandgap than the peripheral annular region.