Novel borothermal route for the synthesis of lanthanum cerium hexaborides and their field emission properties

Abstract

The present study describes the development of a simple approach to stabilize polycrystalline lanthanum cerium hexaborides without using any flux and at ambient pressure. The nanostructured lanthanum–cerium borides were synthesized using hydroxide precursors. These precursors (La_1−xCe_x (OH)₃, x=0.1, 0.2, 0.3 and 0.5) were synthesized via hydrothermal route in the presence of Tergitol (surfactant, nonylphenol ethoxylate) as a capping agent. The precursors on heating with boron at 1300 °C lead to the formation of nanostructures (cubes, rods and pyramids) of lanthanum cerium hexaboride. We have investigated the field emission behaviour of the hexaboride films fabricated by spin coating. It was observed that the pyramidal shaped nanostructures of La_0.5Ce_0.5B₆ shows excellent field emission characteristics with high field enhancement factor of 4502.