Abstract: We disclose targets for generating x-rays using electron beams, along with their method of fabrication. The targets comprise a number of microstructures fabricated from an x-ray target material arranged in close thermal contact with a substrate such that the heat is more efficiently drawn out of the x-ray target material. This in turn allows irradiation of the x-ray generating substance with higher electron density or higher energy electrons, which leads to greater x-ray brightness, without inducing damage or melting. The microstructures may comprise conventional x-ray target materials (such as tungsten) that are patterned at micron-scale dimensions on a thermally conducting substrate, such as diamond. The microstructures may have any number of geometric shapes to best generate x-rays of high brightness and efficiently disperse heat. In some embodiments, the target comprising microstructures may be incorporated into a rotating anode geometry, to enhance x-ray generation in such systems.