Ce doping enhances the field emission performance of single crystal La0.75Ce0.25B6 FEAs: Experimental and theoretical exploration

Abstract

In this study, the effect of Ce doping on field emission properties of single crystal La_0.75Ce_0.25B₆ field emission arrays (FEAs) was studied by utilizing a combination of experimental and density functional theory (DFT). The spark plasma sintering (SPS) technology combined with optical zone melting method were used to prepare Ce doped single crystal La_0.75Ce_0.25B₆ with good quality, and then uses femtosecond laser direct writing technology to prepare a FEAs on its crystal surface. The single crystal quality, field emission performance FEAs of La_0.75Ce_0.25B₆ single crystal were tested. The curvature radius of the prepared FEAs with uniform morphology and surface nanostructure is about 0.5 μm. The femtosecond laser does not damage the surface structure and phase of the FEAs. The field emission test results of the FEAs indicate that its starting electric field is 1.9 V/μm. The emission current density with good emission stability could reach 1.0 mA under the electric field of 6.8 V/μm. DFT calculated results show that Ce doping enhances the field emission performance of single crystal La_0.75Ce_0.25B₆ FEAs with a lower work function by optimizing the energy band structure (Fermi level position and electron effective mass) and 4f-5d electron orbital distribution.