In situ field emission study of TiN-coated ZnO nanowires

Zinc oxide (ZnO) nanowire field emitters have significant applications in vacuum microelectronic devices. In this work, field emission properties of titanium nitride (TiN)-coated ZnO nanowires were investigated in situ using nanoprobe technique. The TiN layer was deposited on the ZnO nanowires by direct-current magnetron sputtering. Statistical analysis of the results from in situ field emission measurement on individual nanowire shows that the turn-on voltage (corresponding to emission current of 0.1 nA) was higher after TiN coating when measured at a fixed anode-to-cathode distance. The maximum current was further measured, and higher maximum emission current was obtained from the TiN-coated ZnO nanowires. The higher turn-on field was explained by the smaller penetration length in the ZnO nanowire after coating, and the increased maximum current was attributed to the increased electrical and thermal conductance after TiN coating.