A solar-powered autonomous CMOS circuit structure is fabricated with monolithically integrated photovoltaic solar cells. The structure includes a device layer including an integrated circuit and a solar cell layer. Solar cell structures in the solar cell layer can be series connected during metallization of the device layer or subsequently. The device layer and the solar cell layer are formed using a silicon-on-insulator substrate. Subsequent spalling of the silicon-on-insulator substrate through the handle substrate thereof facilitates production of a relatively thin solar cell layer that can be subjected to a selective etching process to isolate the solar cell structures.