Low-temperature thermionic emitters using metal-semiconductor composites

Abstract Small metal particles (10–100 nm in size) buried in semiconductor matrices provide a source of electrons which can be optically or thermally excited into the semiconductor across the metal-semiconductor Schottky barrier. These electrons which are now in the conduction band of the semiconductor have only to surmount the surface barrier of the semiconductor, i.e. the electron affinity E A , in order to escape into vacuum. Since Schottky barriers can be made considerably smaller than the bandgap E g of most common semiconductors (1–3 eV), the threshold for electron emission into the vacuum is reduced, i.e. ( E Schottky + E A ) E g + E A ). Some preliminary results on Au-CuInSe 2 composites provide strong support for these ideas.