Light-induced, room-temperature hydrogen gas detection based on SnO2 quantum Dots/p-Si

Abstract

The continuous monitoring of the hydrogen gas level under low-temperature conditions is vital to prevent explosive accidents. Metal oxide-based chemoresistors have attracted significant attention owing to their excellent gas sensitivity. However, high operating temperature required to remove adsorbed oxygen species is still considered as an obstacle, limiting the application of the system. In addressing the temperature issue, this study introduced an approach in which a gas interaction layer was separated from the signal-sensing region. The proposed two-terminal device comprises a gas interaction layer of SnO2 quantum dots (QDs) and a p-doped silicon (p-Si) region characterized by high electronic conductivity and light sensitivity. Through visible light illumination, the recombination between gas interaction-induced electrons and photo-generated holes induces a change in output photocurrent, enabling room-temperature gas sensing without additional temperature control. Using this gas sensing scheme, the proposed sensor showed impressive gas detection performance in the low-temperature range, achieving a detection range of a few parts per million (ppm) in concentration (limit of detection range: 9.46–50 ppm).