Enhanced field emission properties from oxygen-deficient α-Fe2O3 nanorod arrays

Hydrothermally grown FeOOH nanorods were successfully transformed into oxygen-deficient alpha-Fe2O3 nanorod arrays (HNAs) with a pure phase by annealing in an Ar atmosphere at the temperatures of 300-550 degrees C. It was found that the oxygen-deficient HNAs exhibited an increased oxygen vacancy (Fe2+ site) concentration with the increase in annealing temperature. On the basis of the experimental results, a possible mechanism for the formation of the oxygen-deficient HNAs is hypothesized. In particular, the turn-on field of oxygen-deficient HNAs can be optimized to 1.45V/mu m, which is much smaller than that of pristine HNAs. The emission current density can reach 3.37mA/cm(2) at 4.86 V/mu m for the oxygen-deficient HNAs. Such excellent field emissions properties are the best performances reported till date for a pristine alpha-Fe2O3 field emitter and are mainly attributed to the increased conductivity and decreased work function resulting from the introduced oxygen vacancies. (C) 2016 American Vacuum Society.