Oxide semiconductor gas sensors are widely used for detecting toxic, explosive, and flammable gases due to their simple structure, cost-effectiveness, and potential integration into compact devices. However, their reliable gas detection is hindered by a longstanding issue known as humidity dependence, wherein the sensor resistance and gas response change significantly in the presence of moisture. This problem has persisted since the inception of oxide semiconductor gas sensors in the 1960s. This paper explores the root causes of humidity dependence in oxide semiconductor gas sensors and presents strategies to address this challenge. Mitigation strategies include functionalizing the gas-sensing material with noble metal/transition metal oxides and rare-earth/rare-earth oxides, as well as implementing a moisture barrier layer to prevent moisture diffusion into the gas-sensing film. Developing oxide semiconductor gas sensors immune to humidity dependence is expected to yield substantial socioeconomic benefits by enabling medical diagnosis, food quality assessment, environmental monitoring, and sensor network establishment.

Citations

• Colorimetric Gas Sensors Based on Metal Oxide and Metal Halide Nanostructures for Rapid Detection of Hydrogen and Ammonia Leakage in Eco-Friendly Marine Vessels
  Haemyeong In, Changyun Kim, Kwonho Jang, Chae Young Woo, Hyung Woo Lee, Ji Wook Yoon, Myungkwan Song, Kang Hyun Park
  Applied Science and Convergence Technology.2026; 35(5): 151.     CrossRef