Properties of Si/Cs/O nanocluster thin films with negative electon affinity

摘要

Thin films of Si/Cs/O nanoclusters have been synthesized by the technique of supesaturated thermal vaportization of Si and Cs in an oxygen background gas. These films, which were deposited onto conducting or semiconducting substrates, exhibit negative electron affinity (NEA) as evidenced by ultraviolet photoemission spectroscopy (UPS). Photo and feld electron emission properties of these anocluster films were investigated with photo-electron emission microscopy (PEEM), field electron emission microscopy (FEEM), and current-voltage measurements. Flat cathodes covered with tin films of Si/Cs/O nanoclusters exhibited high current outputs and low turn-on fields. The films' NEA is unaffected by air exposure and is stable to high temperature annealing (550 deg C). A field emission display unit with a simple diode structure containing a flat cathode coated with a patterned thin film of Si/Cs/O nanoclusters has also been built to demonstrate that potential applicaton of this material in cold cathode electron emitting devices, particularly field emission flat panel displays.