Zinc Oxide Tetrapod Synthesis and Application for UV Sensors

Zinc oxide tetrapods (ZnO-Ts) were synthesized by air oxidation of zinc vapor. For stable production of the ZnO-Ts at the furnace temperatures of 900 °C, the lowest evaporator temperature was found to be 480 °C. Aerosol measurements showed that the fraction of naturally charged particles decreased with evaporator temperature from 89 % at 480 o C to 43 % at 420 o C. Various UV sensors were prepared to study the response and reset times and the On/Off ratio as a function of the ZnO-T concentrations, interelectrode distance and air humidity conditions. The presence of humid air was found to increase the conductivity of the ZnO-T sensors and to lower the response and reset times as well as On/Off ratio to 98, 96 and 88 %, respectively.