A semiconductor structure is bonded directly to a diamond substrate by Van der Waal forces. The diamond substrate is formed by polishing a surface of diamond to a first degree of smoothness; forming a material, such as diamond, BeO, GaN, MgO, or SiO2 or other oxides, over the polished surface to provide an intermediate structure; and re-polishing the material formed on the intermediate structure to a second degree of smoothness smoother than the first degree of smoothness. The diamond is bonded to the semiconductor structure, such as GaN, by providing a structure having bottom surfaces of a semiconductor on an underlying material; forming grooves through the semiconductor and into the underlying material; separating semiconductor along the grooves into a plurality of separate semiconductor structures; removing the separated semiconductor structures from the underlying material; and contacting the bottom surface of at least one of the separated semiconductor structures to the diamond substrate.