NEGATIVE ELECTRON-AFFINITY SURFACES OF ALUMINUM NITRIDE AND DIAMOND

The electron affinity of diamond and AlGaN surfaces are studied by UV photoemission spectroscopy. It is shown that H terminated diamond surf aces exhibit a negative electron affinity while oxide terminated surfa ces exhibit a positive electron affinity. In addition, thin metal laye rs can also induce a NEA on both (100) and (111) surfaces of diamond. Photoemission results of AlGaN alloy films grown on 6H-SiC indicate a negative electron affinity for as-prepared and air exposed surfaces wi th high Al concentrations.