Richardson Dushman Research Articles

Thermionic emission in silicon at temperatures below 30 K

Experimental results on the injection of carriers into the i region of silicon p-i-n diodes at temperatures below 30 K are described and a simple model is presented to explain the observed I-V characteristics. A range of temperatures is identified in which it is argued that thermionic emission into the i region can be observed unmasked by other effects. The model generalizes the Richardson–Dushman equation to include the effect of impurity bands and a finite transition region between heavily doped and lightly doped regions. As an application, a fast nondestructive means of determining the abruptness of doping profiles is suggested.

Promising cathode materials for high brightness electron beams

Materials for high brightness cathodes are evaluated by defining a figure of merit, which is based on the Richardson–Dushman equation. By calculating the figure of merit of borides, carbides, nitrides, and some refractory metals, it is concluded that carbides of transition metals such as TiC, ZrC, TaC, and HfC are promising for high brightness cathodes.

On the Constant "A0" in the Richardson–Dushman Equation

The enormous deviations in the observed magnitudes of the constant "A0" of the Richardson–Dushman equation from the theoretical value for various materials appear to be roughly related to the heats of atomization of the latter. This has been explained in terms of some erosion of the cathode during the measurements.