Pulsed Laser Deposition Of Lab6 Thin Films As Thermionic Emitters

Lanthanum hexaboride (LaB6) thin-films were grown both by ns (ArF, 193 nm) Pulsed Laser Deposition (PLD). LaB6 layers can act as efficient electron emitters for high temperature (< 2000 °C) thermionic cathodes due to their low work function (around 2.3 eV). The physical properties of the thin-films deposited by PLD were optimized by varying target-substrate working distance (in the range 30-100 mm), bias voltage substrate (with or without -100 V) and process atmosphere (vacuum and Ar pressure). Scanning electron microscopy, and x-ray spectroscopy (XPS) were used to investigate the properties of the deposited thin-films. Ultraviolet Photospetroscopy (UPS) Thermionic emission measurements were performed to evaluate the work functions of LaB6 deposited on metallic substrates.