Abstract

By coadsorption of cesium and oxygen in ultrahigh vacuum on a semiconductor surface, it is possible to lower the work function to ~1 eV. By such an activation on a p- type GaAs surface, a negative electron affinity (NEA) situation is obtained, where the vacuum level at the surface is lower in energy than the bottom of the conduction band in the bulk material. In such a system the conduction electrons are no longer confined in the solid and may be easily emitted into vacuum.

© 1990 Optical Society of America