Effect of praseodymium coating on electron emission from a nanoscale gold field emitter array

Although field emission devices are inherently robust to high temperature and radiation environments as well as have high switching speeds, their development has been hindered by high voltages that are typically required for their operation. In this work, we investigate the effect of thin-film praseodymium (Pr) coating on the emission characteristics of a lateral gold (Au) field emitter array. Because Pr has a significantly lower work function than Au, it is expected to increase the field emission measured current. Pr is deposited onto the device via thermal angled evaporation in a custom-built vacuum chamber with in situ electrical characterization capability. Our experiments demonstrate that a 10 nm-thick Pr layer reduces the turn-on voltage by almost half compared to the noncoated Au structure. These results are promising for the development of power-efficient, low voltage field emission electronics.