Photoelectric and Optical Properties of Sb-Cs and Sb (Mg)-Cs Films

Abstract

The dark current in photomultiplier tubes has recently come into question in want of larger electron multiplication, and thus it is necessary to develop a new photoemitter with less dark current.
Sb-Cs photoemitter is being used extensively as the photocathode of photomultiplier tubes but the dark current of the order of 10^-15A/cm² therein produced is not to be overlooked.
For reducing the dark current, photoelectric and optical characteristics of Sb-Cs photoemitter and Sb (Mg)-Cs photoemitter (reported by N. Schaetti) are studied and the mechanism of dark current reduction may be suggested. The reduction may be considered due to the increase of the acceptor density by the addition of Mg but not due to the lowering of Fermi level by the addition of other elements as W. E. Spicer postulated. Further study is needed for final conclusion.