Large-scale growth of ultrathin MgO nanowires and evaluate their field emission properties

One-step thermal evaporation route was developed to produce large quantities of ultrathin magnesium oxide (MgO) nanowires on a steel mesh substrate. The synthesis of MgO nanowires was carried out in a tube furnace under air pressure using initial N2 gas at 900 °C and subsequent N2/O2 atmosphere reaction. Scanning electron microscopy and X-ray diffraction show that the products are very pure of crystalline MgO nanowires with diameter from 10 to 50 nm and lengths range from several hundred nm to more than 10 μm. High-resolution transmission electron microscopy and its corresponding electron pattern reveal that these MgO nanowires are single crystals with preferred growth direction along 〈1 0 0〉. Field emission (FE) properties on MgO nanowires show that its emission currents density can reach 2.1 mA/cm2 at electric field of 6.46 V/μm and have a very low turn-on field emission (1.3 V/μm). These results suggest that ultrathin MgO nanowire can be an excellent FE material candidate.