Field- and photon-enhanced field emission from thin-film field-emission devices

Thin-film sandwich devices of CdS-SiO-metal have been made. They have current/voltage behaviour characteristics of field emission from semiconductors. With reverse bias, the current is very much smaller. The field-emission current is greatly enhanced by illuminating the device with 2.41 and 2.54eV photons (from an argon-ion laser). Under pulsed laser excitation (pulse duration 1 ¿s) the enhanced emission persisted for more than 20ms. These experiments are analogous to some previous work on vacuum field emission. A possible mechanism for the enhanced emission is discussed.