Promising electron field emitters composed of conducting perovskite LaNiO3 shells on ZnO nanorod arrays

Abstract

We report a semiconductor–perovskite composite system with promising field emission properties. The composite system was fabricated by sputtering perovskite LaNiO3 (LNO) shells on one dimensional (1D) well-aligned hydrothermally produced ZnO nanorod arrays (ZNAs). The ZNA–LNO core–shell hetero-structures were demonstrated to be much more efficient field emitters than ZNAs. Since the work function of LNO (4.5 eV) is lower than that of ZnO (5.3 eV), a shallow well is formed in thermal equilibrium in the ZNA–LNO heterojunction. When an electric field is applied, the produced well is of much benefit for the flow of electrons from the GZO seed layers through the ZNA to the LNO shells. Consequently, the emission of electrons into vacuum by tunneling is easily realized due to the low work function of the LNO coatings. Our 1D semiconductor–perovskite composite system provides a prospect for the development of practical field emission electron sources.