Low-resistance (NH4)xWO3 Nanowire Sensors for Acetone Recognition Operating at Low Voltage with Low Power Consumption

A small-size and low-power consumption acetone sensor for the possible integration with LSIs was realized by a low-resistance $(\text{NH}_{4})_{\mathrm{x}}\text{WO}_{3}$ nanowire. By utilizing hydrothermal synthesis, a large amount of $\text{NH}_{4}{}^{+}$ was inserted in the hexagonal tunnel of $h-\text{WO}_{3}$ nanowires. The insertion and the activation of $\text{NH}_{4}{}^{+}$ were confirmed by FT-IR and XPS. The low nanowire resistance of $1.9\ \mathrm{k}\Omega$ made it possible to realize self-Joule heating effective to activate catalytic reaction with low applied voltage of 0.60 V and low power consumption of 0.11 mW. With the self-Joule heating, selective acetone sensing against ethanol was successfully demonstrated.