Structures including III-V compound semiconductor-based devices and silicon-based devices integrated on a semiconductor substrate and methods of forming such structures. The structure includes a substrate having a device layer, a handle substrate, and a buried insulator layer between the handle substrate and the device layer. The structure includes a first semiconductor layer on the device layer in a first device region, and a second semiconductor layer on the device layer in a second device region. The first semiconductor layer contains a III-V compound semiconductor material, and the second semiconductor layer contains silicon. A first device structure includes a gate structure on the first semiconductor layer, and a second device structure includes a doped region in the second semiconductor layer. The doped region and the second semiconductor layer define a p-n junction.