Improved field emission properties of α-Fe2O3 nanoflakes with current aging treatment and morphology optimization.

α-Fe2O3 nanomaterials were synthesized by thermal oxidation of pure iron foil and the effects of current aging treatment and morphology on their field emission properties were systematically investigated. The current aging treatment was found to be an efficient method to improve the field emission properties of α-Fe2O3 nanoflakes. The emission current density was largely enhanced from 0.05-5.70 mA cm-2 under an applied electrical field of 7.8 MV m-1, and their threshold field decreased from than 11.0-6.6 MV m-1 after the current aging treatment. The mechanism of the improvement in the field emission performance of α-Fe2O3 nanoflakes induced by the current aging treatment is discussed. α-Fe2O3 nanostructures with various morphologies were synthesized by adjusting the growth temperatures between 300 °C-450 °C to optimize their morphologies. α-Fe2O3 nanoflakes synthesized at 350 °C were superior field emitters with a low threshold field of 5.1 MV m-1, high current density of 63.4 mA cm-2, and stable emission, which demonstrated that α-Fe2O3 nanoflakes could be a promising material for application as field emitters.