title: Nitrogen-mediated wet-chemical formation of carbon nitride/ZnO heterojunctions for enhanced field emission.
abstract: Heterojunction structures of nanocrystalline materials are of great importance in scientific and industrial research for their potential applications in nanoscale electronics and photonics. Here, we report a simple wet-chemical method of nitrogen-mediated growth of ZnO nanocrystals on carbon nitride (CNx) nanotubes. SEM and TEM analyses show self-organized ZnO nanoflowers on CNx stems. PL spectra exhibiting a blue emission at 449 nm confirms the junction formation between CNx and ZnO. The field emission (FE) properties of CNx-ZnO film are greatly improved over those of pristine CNx. The turn-on and threshold fields for bare CNx film are 1.70 and 2.95 V/v, whereas those for CNx-ZnO hybrid are found to be 0.75 and 1.3 V/microm, respectively. This significant downshift in the turn-on and threshold fields is believed to occur via lowering of the Schottky barrier at the metal-semiconductor interface. Three-dimensionally blossomed ZnO nanopetals with multiple sharp tips effectively enhance the FE performance. Moreover, this heterojunction reinforces the electron emission lifetime and protects the CNx tubes against thermal degradation.
authors.affiliation: 21st Century COE, Department of Materials Science and Engineering Meijo University, Nagoya 468-8502, Japan.
authors.forename: Kaushik
authors.initials: K
authors.lastname: Ghosh
authors.forename: Mukul
authors.initials: M
authors.lastname: Kumar
authors.forename: Huafeng
authors.initials: H
authors.lastname: Wang
authors.forename: Takahiro
authors.initials: T
authors.lastname: Maruyama
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Ando