A semiconductor structure includes a thin-film device layer, an optoelectronic device disposed in the thin-film device layer, and a surrogate substrate permanently attached to the thin film device layer. The surrogate substrate is optically transparent and has a thermal conductivity of at least 300 W/m-K. The optoelectronic device excitable by visible light transmitted through the surrogate substrate. A method of fabricating the semiconductor structure includes fabricating the optoelectronic device in a device layer thin-film of SiC on a silicon wafer of a first diameter, transferring the device layer thin-film of SiC from the silicon wafer, and permanently bonding the device layer thin-film to a SiC surrogate substrate of a second diameter.