Self-assembled ErAs islands in GaAs for THz applications

This paper concerns self-assembled ErAs islands in GaAs grown by molecular beam epitaxy. The nucleation of ErAs on GaAs occurs in an island growth mode leading to spontaneous formation of nanometer-sized islands. Pump–probe measurements indicate that the ErAs islands capture photogenerated carriers on a subpicosecond time scale. This together with the high resitivity of the material allows us to use it as a fast photoconductor. The performance of photomixer devices made from this material is discussed.