Raw data for the manuscript entitled "Direct evidence of low work function on SrVO3 cathode using thermionic electron emission microscopy and high-field ultraviolet photoemission spectroscopy"

Electrically conductive perovskite oxide SrVO3 with its low work function and facile synthesis process has become a very promising electron emission cathode candidate. The SrVO3 cathode in polycrystalline pellet form has been reported to show a reproducible effective work function of about 2.7 eV, suggesting the presence of some fraction of even lower work function patch on the polycrystalline cathode surface. In this study, we used thermionic electron emission microscopy (ThEEM) to study the spatial local work function distribution on the partial [110] SrVO3 cathode surface. ThEEM with a high applied electric field cancels the patch field effect and uncovers the lowest local work function of just 2.1 eV, which is much lower than [001] LaB6 single crystal cathodes (2.7 eV) and comparable to B-type dispenser cathodes (2.1 eV). ThEEM measurement under high applied field also reveals observable electron emission at a very low temperature of just 750 oC. Overall, this study demonstrates that high applied electric field can uncover the lowest work function of SrVO3 cathode surface, comparable to the DFT-predicted value of 2.3 eV of (110) SrVO3 surface. And, if the areas of the low work function patches are increased, it can provide high emission current at reduced temperature and applied electric field which could significantly advance the electron emission cathode research field.This file contains all the raw data of the ThEEM measurement, thermionic and photoemission current measurements using ultra violet photo emission spectroscopy, electron backscatter diffraction (EBSD) measurement, field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS) study on the SrVO3 cathode surface.