Abstract
Efficient photoemission from InAs1−xPx (Cs–O) with a band-gap-limited threshold at 1.4 μ was observed. Indirect measurements of the composition and thickness of the Cs–O low-work-function surface suggest that the surface consists of about one monolayer of Cs, followed by approximately one monolayer of cesium oxide. These data make an interpretation of the low-work-function properties of Cs–O in terms of the heterojunction model (based on the bulk properties of Cs2O) questionable.