Enhanced field electron emission from ZnO nanowires by $\text{Bi}_{0.5}\text{Sb}_{1.5}\text{Te}_{3}$ coating

Joule heating would be generated in the field emission process of the nanowire field emitter. This could induce the rising of the temperature, cause energy loss and lead to melting of the emitter. In this study, in order to make use of the phenomena, a thin layer of thermoelectric
$\mathbf{Bi}_{0.5} \mathbf{Sb}_{1.5} \mathbf{Te}_3$
was coated on the surface of the ZnO nanowires. The field electron emission current from a single nanowire was studied. It was found the emission current of a single ZnO nanowire increased from 11.1 pA to 8.95 nA after being coated with the
$\mathbf{Bi}_{0.5}\mathbf{Sb}_{1.5}\mathbf{Te}_{3}$
film under the same electrical field. The effect of temperature on the field emission was also studied and it was found the field emission was more sensitive to temperature after the coating. It is proposed the enhanced current is related to the built-in potential due to the temperature gradient in the axial direction of the nanowire. Our results are important for exploring new high efficiency energy conversion device.