Metal-Rich Zn-Sn-O-N Channel-Based Thin Film Transistor Photodetectors

Oxide semiconductor photodetectors (PDs) are frequently employed in applications such as the Internet of Things (IoT) due to their high mobility and low off-state current. To balance responsivity and response rate is a common practice in the research of oxide semiconductor PDs. Here, we report a thin film transistor (TFT) PD with high visible-light responsivity and rapid response rate based on a unique metal-rich ZnSnON (ZSON) channel material. The introduction of nitrogen serves to narrow the bandgap, thereby increasing the visible-light responsivity. Meanwhile, the metal enrichment condition created in the channel mitigates the persistent photoconductivity (PPC) phenomena to speed up the response rate. The optimized device demonstrates high responsivities of 253 (@650 nm), 868 (@550 nm), and 1097 (@450 nm) A/W along with short response times (trise/tfall) of 0.38/0.53 s. These PDs not only enhance the interactive capabilities of display products, but also offer promising opportunities in various other application areas.