Self-Powered InGaZnO Ozone Gas Sensors Based on a Metal–Semiconductor–Metal Structure with Asymmetric Interdigitated Electrodes

Traditional semiconductor gas sensors have a single-plane electrode structure; therefore, an external bias voltage is needed to create an electric field to help carriers move within the sensing material. However, the importance of developing self-powered gas sensors is gradually being recognized for their ability to offer energy-efficient and continuous gas monitoring, particularly in harsh environments. In this study, an amorphous InGaZnO (a-IGZO) gas sensor with asymmetric finger electrodes is developed for self-powered gas-sensing applications. By increasing the asymmetric ratio (the width of the positive electrode to the width of the negative electrode) of the Au interdigitated electrodes from 1 to 3, the gas response of the a-IGZO self-powered gas sensors significantly improved from approximately 0 to 60%. A theoretical model grounded in band energy theory is used to elucidate the underlying mechanism of the gas response observed at 0 V in our device. This strategy paves a facile way for monolithically fabricating a self-powered electronic nose with gas sensor arrays.