Zinc oxide nanowire with high sensitivity has been demonstrated to detect chemical substances. However, the sensitivity of ZnO gas sensor is dependence of different working temperatures, which restrict use environment. To improve the senor performance, a self-powered and sensing module combined with thermoelectric chip and gas sensor will be designed and fabricated in this study. Furthermore, we adopt a BiFeO3-coated ZnO nanowire as sensor source. In this work, the ZnO nanowires were growth by low-temperature hydrothermal process and followed by sputtered BFO covering. From the ammonia gas-sensing results, we fi nd that the BFO-coated ZnO nanowire array shows much faster response time and better sensitivity, compared to control ZnO nanowire array.