Effect of phosphorus dopant on photoluminescence and field-emission characteristics of Mg0.1Zn0.9O nanowires

The photoluminescence and field-emission properties of Mg0.1Zn0.9O nanowires (MZO NWs) hydrothermally grown on the p-type silicon (100) substrates with and without phosphorus dopant were investigated in this study. Parts of MZO NWs were treated with PH3 plasma to form phosphorus-doped MZO NWs (PMZO NWs). The MZO and PMZO are wurtzite single crystals, and the surface morphologies of MZO NWs are identical to those of PMZO NWs with an average diameter of 50 nm and a length of 500 nm. The direct band gaps and emitted ultraviolet photoluminescences of the MZO and PMZO NWs are 3.41 eV and 403.8 nm and 3.56 eV and 385.4 nm, respectively. The MZO NWs grown on Si substrates have an emission threshold electric field of 1.8V∕μm (current density of 1.0mA∕cm2) and a field enhancement factor, β, of 3048 while the PMZO NWs show enhanced properties with a threshold electric field of 1.5V∕μm and a β value of 3054. These field-emission properties are also enhanced by illumination, which reveals that the emission behavior is affected by the surface charge state. Therefore, it is suggested that the band structure of MZO NWs has been modulated by phosphorus incorporation.