Photoelectron emission and injection of cleaved mica film

In order to investigate the cause of the phenomenon whereby the current due to photoelectron emission from a mica surface remained almost constant during illumination, the photoemission current was measured for specimens of different thickness and with cathodes of different area. As a result, the contribution of the cathode to the photoelectron emission was found to be that electrons injected from the cathode with the light transmitted to it through the mica compensate the positive charge accumulation in the mica surface. It was also found that the amount of photoelectron emission was influenced not by the photothreshold energy for the electron injection from the cathode, but by the contact potential difference between the mica and the cathode metal, and the polarity of the mica with respect to the metal.<>