Defect-assisted field emission from ZnO nanotrees

The temperature dependence of field emission characteristics from ZnO nanotrees is studied. An evident thermo-enhanced field emission effect is found in field emission from ZnO nanotrees. The turn-on field decreases obviously from 15.3 MV/m to 11.9 MV/m when the temperature increases from 293 to 773K. A defect-assisted emission model is used to explain the results.