A photodiode fabricated using spalling techniques, and method for making the same. The photodiode including a substrate, an optical device semiconductor material layer disposed over the substrate, a p-type contact disposed over the optical device semiconductor material layer, an n-type contact disposed over the substrate, and an adhesion layer for rear illumination adhered to the bottom of the substrate. Both the substrate and the optical device semiconductor material layer comprise at least one of GaN, AlGaN or AlN.