Localized light induced thermionic emission from intercalated carbon nanotube forests

In this work, we studied light induced thermionic emission from potassium intercalated carbon nanotube forests. Several recipes were developed for the intercalation process. The intercalated CNT forest was employed as the emitter of a light activated thermionic emission device. The resulting thermionic device was characterized by studying its current-voltage characteristics when illuminated by a focused laser beam. Based on the amount of current drop vs time, the value of workfunction reduction was estimated to be about 0.7 eV. Current-voltage characteristics were obtained at several incident light powers. Thermionic emission of potassium ions from the surface of the forest was observed at lower biases. In another set of experiments, in-situ intercalation of carbon nanotube forests was accomplished. The current-voltage characteristics were captured at different times during a period of 72 hours. It was observed that the workfunction has been reduced by 1.1 eV.