Stationary High-Field Domains in the Range of Negative Differential Conductivity in CdS Single Crystals

In CdS crystals with an $N$-shaped negative differential conductivity range, stationary high-field domains adjacent to the electrodes are observed. With increasing applied voltage these steplike domains increase in width, staying attached to the cathode until they fill the entire crystal; then a still higher-field domain forms at the anode and increases in width. These domains can be explained within an earlier published theory, and allow the determination of electron densities at the cathode-CdS boundary and in the field-quenched region. The analysis of these stationary domains presents a new tool for work-function (metal-semiconductor) investigations.