Cs–O negative-electron-affinity surfaces on silicon

The thickness of cesium and oxygen deposits required to produce negative electron affinity on semiconductors is not clear from published data. Photoemission measurements show that, for heavily doped p-type silicon, negative electron affinity can be achieved with either monolayer or thick deposits of cesium and oxygen, whereas deposits of intermediate thickness are less effective. The results also show that for silicon the lowest effective work function can be achieved by monolayer activation.