Abstract: A photocathode manufacturing intermediary article (24) includes a substrate layer (26), and an active layer (20) that is carried by the substrate layer (26). The active layer (20) includes photoemissive alkali antimonide material that is epitaxially grown on the substrate (26).

Abstract: A photocathode manufacturing intermediary article (24) includes a substrate layer (26), and an active layer (20) that is carried by the substrate layer (26). The active layer (20) includes photoemissive alkali antimonide material that is epitaxially grown on the substrate (26).

Abstract: An apparatus and method for non-destructive measuring of local carrier concentration and bandgap in a semiconductor such as gallium arsenide or gallium aluminum arsenide. A high energy source of photons, e.g. a laser, photo injects carriers on the surface of the semiconductor causing a change in the semiconductor's surface photo reflectance. The fractional change in photo reflectance is measured for a plurality of the photon energies sufficient to identify several Franz-Keldysh peaks, and the photon energies corresponding to these peaks. This information is used to infer the local electric field strength and carrier concentration of the semiconductor as well as semiconductor's bandgap. By noting variations in these parameters throughout the bulk semiconductor, one can identify fatal fabrication flaws in the semiconductor crystal before time and money is expended to fabricate complicated semiconductor architectures in the crystal.