Highly Efficient Field Emission Properties of Vertically Aligned 2D CuSe Nanosheets: an Experimental and Theoretical Investigation

We report the synthesis of klockmannite (CuSe) via a three-probe electrochemical set-up (chronoampereometry). The structural properties are examined by X-ray diffraction and Raman spectroscopy. Field emission scanning electron Microscope (FESEM) analysis revealed the formation of vertically aligned CuSe nanosheets with an average thickness of 34 nm and an average lateral size of 700 nm. The CuSe nanosheets exhibit impressive field electron emission characteristics with a turn-on field of 1.4 V/μm for 10 μA/cm2 emission current density. Also, a high current density of 5.8 mA/cm2 is observed at a relatively low applied field of 3.1 V/μm. Complementary first-principles DFT calculations show that CuSe displays metallic conductivity, and the (001) surface has a low work function of 5.12 eV, which is believed to be responsible for the impressive field emission characteristics. The data underpinning the work is available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 3 datasheets named according to their Figure numbers as they appear in the manuscript. The experimental data for XRD, current density vs applied field, Fowler–Nordheim (F-N), emission current stability (I-t) are provided. The data for the optimized structures of the bulk CuSe, CuSe(001) surface, the projected density of states (PDOS), and electrostatic potential for the (001) surface are also given.