Electrical properties of gold-silicon barriers were studied in some detail. The reverse leak age current of these barriers is shown to be caused by lowering of the barrier due to the image force effect. The thermal activation energy of the saturation current was found to be 0.799 eV, identical to the height of the Au-Si barrier. The barrier height, saturation current density, and ideality of Pt, Pd, Ag, Ni and Cu barriers to Si are presented. Two methods for fabricating hot electron triodes are described. Large area structures, made by pressing together a silicon-gold-silicon sandwich, do not exhibit triode characteristics and are limited by particulate matter and deviations from flatness. Triodes with point contact emitters of silicon and gallium arsenide were fabricated and their current-voltage characteristics are presented. Current transfer ratios as high as 0.75 were observed.