Enhancement of field electron emission in topological insulator Bi2Se3 by Ni doping

Abstract

Nanostructures of bismuth selenide (Bi₂Se₃), a 3D topological insulator material, and nickel (Ni) doped Bi₂Se₃ samples were prepared by a hydrothermal method to explore the field emission properties. An enrichment in the field electron emission (FE) properties in terms of the threshold and turn-on field values of Bi₂Se₃ and Ni doped Bi₂Se₃ nanostructures was measured at a base pressure of ∼1 × 10⁻⁸ mbar. Using the background of the Fowler–Nordheim (FN) theory a field enhancement factor (β) of 5.7 × 10³ and a threshold field value of 2.5 V μm⁻¹ for 7.5% Ni doped Bi₂Se₃ were determined by investigating the J–E plot of the FE data. The value of β is three times higher than that of pure Bi₂Se₃ confirming the superior FE properties. The emission current was found to be very stable with the property of long standing durability as a negligible amount of variation was observed when measured at a constant value of 5 mA for 3 hours. The experimental results signify many opportunities for potential applications of Ni doped Bi₂Se₃ as a source of electrons in scanning as well as transmission electron microscopy, flat panel displays and as an X-ray generator, etc.