Highly Crystallized Tin Dioxide Microwires toward Ultraviolet Photodetector and Humidity Sensor with High Performances

Abstract The rapid development of artificial intelligent and internet of things calls for high‐performance multifunctional devices for synchronous detection of a wide variety of environmental signals, such as gas, light, and humidity. Herein, highly crystallized tin dioxide (SnO 2 ) microwires (MWs) with low density of point defects are synthesized by the chemical vapor deposition method and constructed into a multifunctional device for photo and humidity sensing. The device shows excellent photoelectric performances, for example, ultralow dark current of ≈10 −13 A, ultrahigh on–off ratio of >10 7 , UV/visible rejection ratio of R 300 nm / R 400 nm > 10 7 , specific detectivity ( D *) of 1.16 × 10 15 Jones, linear dynamic range (LDR) of 152 dB, high responsivity of 18 A W −1 , and fast photoresponse speed of t rise / t decay = 2.7 µs/2.5 ms at 5 V bias. Furthermore, the p‐CuI/n‐SnO 2 heterojunction shows outstanding self‐powered properties, such as responsivity of 8.98 mA W −1 , specific detectivity of 1.98 × 10 12 Jones and LDR of 106 dB at 0 V bias. Additionally, the SnO 2 MWs also show high sensitivity to ambient humidity changes. Therefore, the SnO 2 MWs show high potential for multifunctional applications, such as UV photodetector and humidity sensor.