Zhen Cui

GaN nanowire field emitters with the adsorption of Pt nanoparticles

We report Pt NP coated GaN NWs through CVD method and the fabrication of their field emitters. Pt NPs are attached on the top and surfaces of GaN NWs. With the Pt NP coating, it is found that the turn on field is reduced from 3.3 V μm−1 to 2.7 V μm−1 and the work function is decreased from 4.1 eV to 3.22 eV. In addition, DFT calculation results indicate that higher local electron states, which appear around the Fermi level, are mainly formed from N-2p, Pt-6s, and Pt-5d orbital hybridization, and will provide more electrons to the conduction band at a given operating voltage. Consequently, the field emission performance of GaN NWs can be effectively boosted by adsorbed Pt. Moreover, Pt NP coated GaN NWs are promising for electron emission devices, field emission displays and vacuum nano-electronic devices.

Synthesis and excellent field emission properties of three-dimensional branched GaN nanowire homostructures

Three-dimensional branched GaN nanowire homostructures have been synthesized on the Si substrate via a two-step approach by chemical vapor deposition. Structural characterization reveals that the single crystal GaN nanowire trunks have hexagonal wurtzite characteristics and grow along the [0001] direction, while the homoepitaxial single crystal branches grow in a radial direction from the six-sided surfaces of the trunks. The field emission measurements demonstrate that the branched GaN nanowire homostructures have excellent field emission properties, with low turn-on field at 2.35 V/μm, a high field enhancement factor of 2938, and long emission current stability. This indicates that the present branched GaN nanowire homostructures will become valuable for practical field emission applications.