Pulsed-laser treatment of solution-grown ZnO nanowires in nitrogen: Enhancing in electrical conduction and field emission

Pulsed-laser (neodymium doped yttrium aluminum garnet; 1.06 mu m in wavelength) treatments were performed on zinc oxide (ZnO) nanowires (NWs) in nitrogen. It results in nitrogen doping of ZnO, mainly with chemical states of N(2) at oxygen sites, which is demonstrated by x-ray photoelectron spectroscopy studies. The laser treated ZnO NWs show significant improvement in electrical conduction and field emission. Typically, with the critical treated conditions of peak power 400 W and pulse duration 2 ms, NWs with the highest conductivity of 1.43x10(-2) S/cm was obtained. It is one order of magnitude higher than that of the as-prepared NWs (1.20x10(-3) S/cm). These NWs show better field electron emission properties. The turn-on field is 2.0 MV/m and a current density of 5.3 mA/cm(2) can be obtained at a field of 3.0 MV/m. The underlying mechanisms related to the enhancing effect of conduction and field emission were discussed. The pulsed-laser treatment may be developed toward a technique for application in the study of nanoelectronic devices using NWs.