Photoemission and Band Structure of the Semiconducting Compound CsAu

The energy distribution of the photoelectrons and the quantum efficiency of the photoemission from CsAu were measured in the spectral range from 1. 6 to 6. 2 ev. From the measurements the following conclusions were drawn: For h>4. 0 ev, photoelectrons are excited principally from the valence band; for h<4. 0 ev, photoelectrons are excited from states near the bottom of the conduction band. A bandgap of 2. 6 (0. 2) ev and an electron affinity of 1. 5 (0. 2) ev are deduced.